As electric intelligent vehicles advance, drive-by-wire systems are increasingly adopted, and the thermal reliability of electromechanical brake (EMB) motors—the key actuators—remains safety-critical. Under stalled-rotor operation, unequal DC currents are typically applied to the three phases, producing nonuniform winding heating. Conventional thermal models can miss the associated tangential heat-transfer effects, increasing the risk of phase-wise end-winding hot spot. This paper analyzes EMB motor thermal behavior under stalled-rotor conditions using a modular 3-D lumped-parameter thermal network (LPTN). First, a standardized tooth module with external interfaces is developed. Its internal parameters are informed by experiments and computational fluid dynamics (CFD) and identified via particle swarm optimization (PSO), allowing the module to be encapsulated for reuse. Next, based on the machine topology, a minimal motor is derived and multiple tooth modules are interconnected through

Duan, Yanlong, Xiong, Lu, Wang, Xinjian, Zhuo, Guirong, Zeng, Jie

Air Bind Energy Prediction in Door Closing Event Through CFD & Its Accuracy Validation with Physical Test

2026-01-0483

4/7/2026

In the automotive industry, the perceived quality of a vehicle is heavily influenced by the ease and effort required to close its doors (which is governed by total door closing energy), particularly when all windows and other doors are closed. A major contributor to increased door closing energy is the air bind energy, a phenomenon caused by the rapid compression of trapped air within a sealed vehicle cabin during door closure. Studies have shown that this transient event leads to a significant rise in cabin pressure. This study presents a Computational Fluid Dynamics (CFD) method to evaluate the impact of air bind energy on door closing during the early stages of vehicle design. By simulating the cabin pressure dynamics during door closure, the research identifies key parameters influencing the air bind energy, such as door closing velocity, pressure relief valve and airflow escape paths. Other mechanical factors like hinge friction, check arm, and door seal etc. are excluded from the

Jagtap, Rohit, Parida, Shaswati, Pimpalkhare, Ninad, Khanna, Susheel, Pasunurthi, Shyam Sundar

Transformer-Based Deep Learning Framework for Efficient Prediction of Automotive Wind Noise

2026-01-0222

4/7/2026

Aerodynamic wind noise is a critical challenge in modern automotive development, particularly with the rise of vehicle electrification and intelligent mobility, where cabin acoustic comfort is a key quality metric. While reliable, traditional methods like wind tunnel experiments and computational fluid dynamics (CFD) simulations are both costly and time-consuming. To address these challenges, we propose a novel Transformer-based framework for rapid and accurate wind noise prediction. Several model improvements, including the physical attention, geometry wave number embedding, hybrid FPS-random downsampling method and frequency separation output heads are properly employed to reduce the GPU memory cost and improve the prediction accuracy. This framework is pre-trained on a large-scale acoustic dataset of nearly 1,000 diverse vehicles generated using Improved Delayed Detached Eddy Simulation (IDDES). From a vehicle's point cloud coordinates, the model directly predicts the surface

Tang, Weishao, Liu, Mengxin, Qin, Ling, Duan, Menghua, Wang, Chengjun, Zhang, Yufei, Wang, Qingyang

Thermal Management Simulation of Liquid-Cooled Energy Storage Batteries Using a Reduced-Order Model

2026-01-0122

4/7/2026

Linear time-invariant (LTI) reduced-order models (ROMs) have been widely used in battery thermal management simulations due to their low hardware requirements, high computational efficiency, and good accuracy. However, the inherent assumption of LTI behavior limits their applicability in scenarios with varying coolant flow rates, where this assumption is no longer valid. To address this limitation, a novel ROM is developed by decomposing the entire battery thermal system into two subsystems. All solid components are modeled as a traditional LTI ROM, while the coolant channel is represented using Newton’s cooling law. The two subsystems are then coupled through the exchange of heat transfer rate and temperature at the fluid–solid interface between the coolant and the cold plate. Model fidelity is further enhanced by introducing a spatially distributed heat flux during the generation of the LTI ROM for solid components. Validation is performed against CFD simulations at both module and

Guo, Jia, Chen, Guijie, Ma, Shihu, Hu, Xiao, Li, Jing, Song, Shujun, Huang, Long

Accurate Simulation of Sealing Process using a GPU-Accelerated Lagrangian Differencing Dynamics Method

2026-01-0492

4/7/2026

The car body consists of many parts, between which there are cavities and gaps that water, dust, and noise can enter. To prevent corrosion and reduce noise, these gaps are sealed with a paste featuring complex non-Newtonian properties. Sealing also serves a cosmetic function for visible areas, which demands high quality for better customer satisfaction. Usually, bead length can reach several meters with a height of 0.5-5 mm and a width of 5-40 mm. In this situation, optimizing the robotic paths and sealant flow can speed up production and reduce costs. Accurate and fast CFD modeling helps with planning the sealing process, shortening vehicle development cycles and minimizing costs. Due to the complexity of vehicle body geometry, arbitrary robotic movements, sealing bead length, free surface, and the complex rheological material properties, traditional CFD simulations have difficulties in modelling this process. This paper presents a new framework for modelling the sealing processes

Panov, Dmitrii Olegovich, Zhu, Huaxiang, Basic, Josip, Zhang, Lingran, Kotian, Akhilesh, Menon, Muraleekrishnan, Borra, Ravi Kanth, Ando, Yuya

Extreme Scale Automotive Aerodynamic Simulations

2026-01-0597

4/7/2026

Achieving an optimal balance between simulation accuracy and computational efficiency remains a central challenge in automotive aerodynamics. While the adoption of AI and machine learning (ML) methods in vehicle development is expected to grow significantly, the demand for highly scalable, computationally efficient, and accurate computational fluid dynamics (CFD) methods persists. The emergence of GPU (graphics processing unit) technology presents new opportunities to deliver cost-effective, high-fidelity, scale-resolving simulations to industrial users. A comprehensive evaluation of Simcenter STAR-CCM+’s parallel scalability and accuracy across extensive CPU and GPU resources was executed on the Frontier supercomputer at Oak Ridge National Laboratory (ORNL). Steady-state and transient aerodynamic scalability simulations were executed using the DrivAer notchback vehicle configuration. Simulation accuracy was evaluated through transient simulations employing the SST-DDES turbulence

Larsson, Torbjörn, Grover, Ronald O., Landi, Simone, Altmann, Peter, McManus, Liam, Dowding, Steven

Machine Learning-Based Prediction of Wind-Induced Interior Noise in Ground Vehicles

2026-01-0599

4/7/2026

In response to increasing customer demand for enhanced passenger comfort and perceived vehicle quality, OEMs in automotive and commercial vehicles are placing significant emphasis on reducing the interior cabin noise. At highway speeds, wind noise is a primary contributor to the overall noise within the vehicle cabin. Conventional approaches to predict vehicle wind noise rely on physical testing, which can only be conducted in the later stages of the design process once a physical prototype is available. Increased adoption of established computational fluid dynamics (CFD) methods has enabled earlier assessment. However, such simulations require several hours to complete, posing a challenge in the context of rapid design iteration cycles. With the growing adoption of artificial intelligence in engineering, machine learning (ML) approaches have been proposed to predict a vehicle’s aerodynamics performance. Nevertheless, development of ML techniques in the context of aeroacoustics

Higgins, John, Fougere, Nicolas, Sondak, David, Senthooran, Sivapalan, Moron, Philippe, Jantzen, Andreas, Bi, Jing, Oancea, Victor

Study of the Vortex Flow over a Generic Open-Wheel Race-Car

2026-01-0649

4/7/2026

Open wheel race cars present a challenge to the aerodynamic designer because of the numerous wakes and vortices created by the various body components. The present study follows the development of a high-downforce race car and investigates possible vortex manipulations to increase its aerodynamic efficiency. The tools used for this study involved computational fluid dynamics and small-scale wind tunnel testing. Once the basic geometry of the racecar was finalized, cost effective measures were tested to improve its downforce to drag ratio. As an example, by fine tuning the position of different body components, such as the rear wing location relative to the underfloor diffuser exit, vehicle’s aerodynamic performance can be modified. The results of both the wind tunnel and the computational investigations indicated that such simple modifications can positively improve the race-car downforce to drag ratio. Also, once the baseline vehicle’s geometry was frozen and observing that the

Okpysh, Christian, Katz, Joseph, Shute, Robin

Elucidation of Flow Mechanisms Modulating Vehicle Wind Noise by Using Large-Scale CFD Simulation

2026-01-0614

4/7/2026

In vehicle development, noise reduction is critical for ensuring passenger comfort. As electric vehicles become prevalent and engine noise is minimized, wind noise becomes more noticeable. Modulated wind noise, which causes a sense of fluctuation due to atmospheric turbulence, wind gusts, and preceding vehicle wakes, can cause significant discomfort. This noise is characterized as a high frequency sound above 1 kHz, modulated at low frequencies owing to the wind velocity and direction fluctuating at several Hz. The mechanisms behind wind noise modulation are not fully understood, and no established countermeasures have been developed. This is because wind noise perceived through the side window is primarily caused by the A-pillar vortex and door mirror wake, which coexist as complex turbulent flows around the vehicle. Therefore, identifying the source of modulated wind noise around vehicles under fluctuating wind conditions is difficult. This study aims to identify the source of the

Tajima, Atsushi, Hirata, Takumi, Ikeda, Jun, Kamiwaki, Takahiro, Wakamatsu, Junichi, Tsubokura, Makoto

Swept Collector Design for the HALO Wind Tunnel

2026-01-0608

4/7/2026

Modern aeroacoustic wind tunnels are required to have flat axial static pressure distribution, very low background noise levels, and minimal low-frequency pressure fluctuations. These characteristics enable accurate measurement of aerodynamic forces acting on a vehicle as well as identification of noise sources. The collector of an open-jet or ¾ open-jet wind tunnel plays a critical role in achieving these goals. Collector self-generated noise contributes to the overall background noise level in the test section, and this contribution has become more significant as other noise sources, such as the main fan, have been addressed through improvements to acoustic treatment. Ever-increasing attention to detail is required to manage noise signatures as the overall facility noise floor is lowered. Furthermore, aspects of collector design that may be beneficial to aerodynamics or pressure fluctuation tend to be some of the worst offenders for noise generation. A new collector configuration was

Best, Scott, Nagle, Paul

Modelling of Cold Start Processes in Proton Exchange Membrane Fuel Cells

2026-01-0496

4/7/2026

In this work, a numerical study is carried out to analyze the cold start process of a three-dimensional proton exchange membrane fuel cell (PEMFC) with a three-parallel serpentine flow channel design. The investigation is mainly focused on developing a transient ice formation model in a computational fluid dynamics (CFD) environment to predict ice formation during subfreezing startup and to analyze its influence on the operation of the fuel cell. The model considers sublimation and de-sublimation processes inside the gas diffusion layer and the catalyst layer. To account for the influence of ice on electrochemical reactions, the local transfer current is reduced depending on the fraction of ice volume present in the porous regions. The proposed model is validated against experimental data, and the comparison shows that the model can successfully reproduce both the successful and the failed cold start cases under different initial temperatures. The study identifies two main factors

ma, Shihu, Champhekar, Omkar, Han, Chao

Leveraging Large Language Models for Natural Language-Driven CAD Automation and Multi-Objective Optimization in Thermal Component Design

2026-01-0506

4/7/2026

The design of thermal components (such as automotive heat exchangers) requires balancing multiple competing objectives—thermal performance, aerodynamic efficiency, structural integrity, and manufacturability. Traditional design workflows rely on manual Computer Aided Design (CAD) modeling and iterative simulations, which are both labor-intensive and time-consuming. Recent advances in Large Language Models (LLMs) present untapped potential for automating parametric CAD generation. However, current LLM-based approaches primarily handle simple, isolated geometric primitives rather than complex multi-component assemblies. This work introduces a progressive framework that leverages fine-tuned LLMs (Qwen2.5-3B-SFT) integrated with the CadQuery CAD kernel to automatically generate parametric geometries from natural language descriptions. As a foundational study, this work focuses on Step 1 of the framework: generating and optimizing isolated geometric primitives (cylinders, pipes, etc.) that

Chaudhari, Prathamesh, Tovar, Andres

Coolant Pump Weep Chamber 3D CFD Transient Simulation for Predicting Coolant Evaporation

2026-01-0485

4/7/2026

This paper presents transient, complex, multi-species, multiphase, 3D CFD transient simulation of engine coolant pump weep chamber for predicting coolant evaporation. The engine coolant pump contains a rotating mechanical face seal to prevent liquid coolant leakage at the rotating interface. During normal engine operation, a small amount of coolant vapor is expressed by this rotating seal; this vapor can condense on solid surfaces within the weep chamber. The coolant collected in weep chamber evaporates from the chamber and exits out of the weep chamber in vapor form. Evaporation rate of the coolant is a primary factor deciding weep chamber size. Evaporation rate of coolant depends on several factors – ambient humidity, ambient temperature, flow of air in and out of the weep chamber, pump temperature, and pump rotational speed. Weep chamber is small in dimensions (~ 100 cm^3) and dependence of coolant evaporation on several factors results in necessity of an accurate and predictive

Tawar, Ranjit Ramchandra, Drechsel, James, Bedekar, Sanjeev, Nallamothu, Sravan

Effect of Renewable Fuel Blends on Particulate Emissions under Medium Engine Load and Injector Coking Conditions in a GDI Engine

2026-01-0301

4/7/2026

Renewable gasoline is blended with fossil gasoline as part of the effort to achieve zero net carbon emissions. This study examined how five gasoline fuels with different hydrocarbon compositions affect engine-out gaseous and particle number (PN) emissions. Gasolines F3 and F4 reduce GHG emissions by 54% and 35%, compared with fossil gasoline. The other three gasolines reduce GHG emissions by 4-9%. Tests were conducted on a single-cylinder GDI engine at 10-14 bar indicated mean effective pressure (IMEP) and 2000 rpm. The injector-tip coking behavior of the test fuels and the resulting PN emissions were also investigated at 10 bar IMEP. Spray plume targets and start-of-injection (SOI) timing were adjusted to examine how the test fuels affected PN emissions. An endoscope was used to identify the sources of soot during fuel combustion. The experimental results show that PN varies with gasoline composition and engine operating conditions. Aromatics and olefins contribute more to injector

Muniappan, Krishnamoorthi, Dahlander, Petter, Helmantel, Ayolt, Alemahdi, Nika, Lehto, Kalle

Flame Velocity and Combustion Behaviour of Ammonia–Hydrogen Blends: A Combined Experimental and Numerical Study

2026-01-0320

4/7/2026

Ammonia is emerging as a promising energy vector for decarbonising the maritime sector. However, its low flame speed can lead to incomplete combustion, reduced engine efficiency, and increased emissions of unburned ammonia (NH3). Blending hydrogen with ammonia helps to address these issues, but the fundamental combustion characteristics of such mixtures remain insufficiently understood. This study examines the combustion dynamics of an NH3–H2 blend containing 30% hydrogen at 3 bar initial pressure. Experiments were performed in a 1.2 L optically accessible constant-volume combustion chamber fitted with a wall-mounted surface spark plug. High-speed shadowgraph imaging with 6,000 fps captured the flame evolution throughout the combustion process. The pressure and temperature values were monitored using piezoresistive pressure transducers and K-type thermocouples. Combustion times and flame extensions were extracted via post-processing of flame images using custom MATLAB algorithms. The

Bodur, Tuna Murat, Bowling, William, La Rocca, Antonino, Cairns, Alasdair

A Holistic Approach to Pre-Chamber Design and Operational Optimization for Diverse Transportation Fuels

2026-01-0310

4/7/2026

As internal combustion engines continue to play a critical role in hybrid on-road and numerous non-road applications, there is a continued push to increase efficiency and minimize tailpipe emissions. However, reduced investment in new engine architectures means retrofittable technologies are favored to continue incremental performance improvements to existing engine platforms. To maintain the relatively low capital cost of engine-based powertrains, these technologies must be low-cost and compatible with the diverse mix of fuels that may be encountered across various market segments in the future. Pre-chambers have shown significant potential for improving spark-ignited engine performance across a wide range of engine sizes, from motorsport applications to stationary power, and operating conditions, from stoichiometric operation to ultra-lean. Understanding the degree to which this central combustion technology must be tailored to optimize its performance with a variety of fuels and

Peters, Nathan, Pothuraju Subramanyam, Sai, Hoth, Alexander, Bunce, Michael

Effects of the Spark Location and Timing in a Heavy-Duty Hydrogen-Fueled Engine

2026-01-0331

4/7/2026

The use of hydrogen in internal combustion engines offers a promising route to lower-carbon propulsion in heavy-duty transportation. However, its distinct combustion characteristics as high flame speed, wide flammability limits, and susceptibility to abnormal combustion, necessitate careful engine and ignition system design. This study numerically investigates the combined effects of spark plug (SP) location and ignition timing on the performance of a heavy-duty diesel engine converted to spark-ignition and operated with hydrogen as fuel at reduced compression ratio. The numerical study aims to guide engine design. Three-dimensional computational fluid dynamics simulations with detailed hydrogen chemistry were conducted to evaluate flame development, and relevant combustion metrics under different loads. Model validation against engine combustion data and hydrogen injection from a low-pressure, high-mass-flow direct injector are also presented. The results demonstrate that SP placement

Menaca, Rafael, Shakeel, Mohammad Raghib, Panithasan, Mebin, Liu, Xinlei, Qahtani, Yasser, AlRamadan, Abdullah, Cenker, Emre, Silva, Mickael, Pei, Yuanjiang, Turner, James, Im, Hong

Aerodynamic Development of Maruti Suzuki Victoris

2026-01-0602

4/7/2026

MSIL (Maruti Suzuki India Limited), India’s leading automotive manufacturer, offers a diverse range of SUVs (Sports Utility Vehicles) in its portfolio. Traditionally, SUVs are associated with an assertive stance and a commanding road presence; however, this bold design language often compromises aerodynamic drag performance. Over the past decade, demand for this segment has surged, while CAFE (Corporate Average Fuel Economy) regulations have become increasingly stringent. To address this growing market need, MSIL conceptualized a new SUV - Victoris - targeted to deliver best-in-class aerodynamic efficiency in MSIL SUV portfolio. This paper details the aerodynamic development process using CFD (Computational Fluid Dynamics) and full-scale WTT (Wind Tunnel Testing). Initially, the aggressive styling of Victoris negatively impacted drag performance. Strategic exterior surface refinements and integration of aero components enabled recovery of aerodynamic efficiency. Key interventions

Dey, Sukanta, Singh, Shekhar, Kumar, Chandan, Alphonse, Felix Regin

From CFD Simulations to Machine Learning: A Comparative Study of ML Tools for Aerodynamic Drag Prediction

2026-01-0598

4/7/2026

This study presents a comparative assessment of two machine learning approaches for predicting aerodynamic drag coefficients (Cd) in automotive vehicle designs using data derived from computational fluid dynamics (CFD) simulations. The first approach employs traditional regression models trained on structured parametric data generated through controlled geometric variations, while the second approach integrates unstructured point-cloud geometry with structured metadata using a multi-modal deep learning framework. Both methods are evaluated within their respective contexts to understand their strengths, limitations and potential roles in automotive aerodynamic workflows. Rather than identifying a single best approach, the study highlights how these methods address different design needs and resource constraints, providing insights for future hybrid strategies that combine interpretability with geometric sensitivity. The work aims to establish a foundation for data-driven aerodynamic

Kumar, Gaurav, Khanna, Susheel

Camera Monitor System Soiling Correlation for a Class-8 Truck Using Lattice Boltzmann Method

2026-01-0596

4/7/2026

As Camera Monitoring Systems (CMS) become an integrated part of the driving experience for current automotive and heavy vehicles, keeping the CMS clean from water, dirt, sand, snow and ice is a main focus of the design process in order to avoid safety issues due to obscured visibility. On-road soiling prevention becomes an important feature when designing the camera and sensor systems. Computational Fluid Dynamics (CFD) analysis can be used to facilitate the design process, to provide important information of the cause of the problems and design mitigation mechanism to prevent the visibility issues. Most of existing work focusses on automotive applications. This paper is targeted for heavy vehicle application. Road tests were performed in Alaska by the testing department. Results from the road test were compared to CFD simulation. This comparison showed a good agreement between CFD and road testing, based on the qualitative soiling deposition patterns, rivulet formation and dispersed

He, Wei, Dasarathan, Devaraj, Linden, Tom, Park, Jeongbin

Automotive Aerodynamics Surrogate Modeling using NVIDIA PhysicsNeMo on Mid-Sized SUV GM Dataset

2026-01-0600

4/7/2026

Aerodynamic simulations are crucial in vehicle design and performance evaluation. Traditionally, these simulations utilize Computational Fluid Dynamics (CFD) techniques to compute flow quantities such as velocity, pressure, and wall-shear stresses. Accurate prediction of these quantities is vital for estimating drag and lift forces, which directly impact fuel efficiency, stability, and acoustics. This study focuses on developing an AI surrogate for aerodynamic design of production mideo-size SUVs using NVIDIA’s PhysicsNeMo framework. Firstly, high-fidelity 3D CFD data are generated using first-principles solvers on 102 different geometry variants at a uniform inlet velocity of 38.89 m/s and a fixed set of boundary conditions. The DoMINO (Decomposable Multiscale Iterative Neural Operator) AI model, part of the PhysicsNeMo framework, is then used to train on this dataset, accurately predicting surface pressure and flow fields around vehicles for rapid estimation of critical aerodynamic

Keum, Seunghwan, Raul, Vishal, Grover, Ronald, Parrish, Scott, Ranade, Rishikesh, Ghasemi, Abouzar, Kamenev, Alexey, Tadepalli, Srinivas

Accelerated Computed Tomography for Spray Characterization

2026-01-0341

4/7/2026

Computed tomography (CT) is a valuable diagnostic technique for visualizing spray plume direction and assessing mixture quality within combustion chambers under engine-relevant conditions. High-speed extinction imaging followed by tomographic reconstruction enables temporally and spatially resolved measurements of liquid volume fraction and plume evolution in multi-plume sprays. Traditionally, tomographic reconstruction requires capturing multiple angular views by rotating the injector and averaging over numerous injections to ensure statistical convergence. This process is time-intensive, particularly due to the large volume of data acquisition and the corresponding delays in data saving, particularly when acquiring many injections per view angle. In this study, we investigate the minimum number of injections required to achieve sufficient CT image quality, thereby significantly reducing experimental time. Two injectors are evaluated: a symmetric 8-hole Spray M injector from the

Yi, Junghwa, Wan, Kevin, Pickett, Lyle

Numerical Study of Gasoline Direct Injection Sprays at Conditions Relevant to Engine Cold-Start Operation

2026-01-0338

4/7/2026

Gasoline direct injection (GDI) remains a key technology for enhancing engine efficiency and meeting regulated engine-out soot limits, particularly when combined with downsizing and boosted operation. The performance of modern GDI engines strongly depends on the in-cylinder spray process, which governs mixture formation and combustion quality under a wide range of operating conditions. In this context, computational fluid dynamics (CFD) is an effective tool for supporting the design and operation of an engine. However, accurately modeling a spray’s evolution —from early to late injections and across varying ambient conditions —remains a major challenge. This study employs a CFD framework with an optimized spray modeling approach to investigate spray morphology and dynamics under various engine cold conditions. Although all simulations are conducted with a single-injection setup, the early- and late-injection cases are designed to emulate different phases of split-injection operation by

Lien, Hao-Pin (Paul), Torelli, Roberto, Zhao, Le, Park, Ji-Woong, Zhang, Anqi, Pei, Yuanjiang, Hwang, Joonsik, Lee, Kyungwon

Upstream Oxygen Sensor Signal Improvement Using the DFSS and Virtual Validation Approach

2026-01-0486

4/7/2026

Combustion stability and emission control remain key challenges for gasoline engines, requiring robust oxygen sensing strategies. The primary function of the upstream exhaust oxygen sensor is to detect the oxygen concentration in exhaust gas for accurate air–fuel ratio control. However, poor signal visibility from individual cylinders across engine speeds can lead to improper combustion prediction and reduced engine efficiency. This work applies a Design for Six Sigma (DFSS) approach to optimize the upstream oxygen sensor configuration in a 2.0 L four-stroke gasoline engine. Conventionally, sensor placement is completed by iterative testing and calibration, which is both time-consuming and cost intensive. The DFSS framework uses input, output, control, and noise factors. Exhaust gas mass flow rate from engine cylinders at different speeds is treated as the input, while the detected oxygen mass fraction is the output. Design parameters such as pipe length, pipe diameter, sensor

Dixit, Manish, Raja, Vinayak, Annabattula, Pallavi

Digital Twin Aerodynamics Model Validation for HALO Wind Tunnel

2026-01-0610

4/7/2026

A simulation-based aerodynamics model of the Honda Automotive Laboratories of Ohio (HALO) Wind Tunnel, a three-quarter open-jet (ground plane) configuration opened in 2022 for full-scale automotive testing, was initiated to support data fusion for more accurate surrogate models in vehicle engineering programs. The objective was to demonstrate that a matched set of boundary values between the physical wind tunnel and the three-dimensional numerical model yield correct responses for several key flow field quantities, starting with the baseline empty tunnel case: (1) streamwise static pressure distribution, (2) evolution of the free shear layers downstream of the nozzle exit plane, and (3) ground-plane boundary layer development. Pressure-based measurement probes were deployed in these regions using a four-axis overhead traverse to acquire validation data in the large facility, including instrument verification between a 14-hole probe and Pitot-static rake. Detached eddy simulation (DES

Patel, Sajan, Disotell, Kevin, Eagles, Naethan

CFD-Guided DoE-ML Optimization Methods in a Heavy-Duty Hydrogen Engine

2026-01-0326

4/7/2026

This study introduces a CFD-guided design of experiments (DoE) and machine learning (ML) framework for the co-optimization of piston and pre-chamber geometries in a passive pre-chamber heavy-duty hydrogen engine operating at medium and low loads. Starting from a reference configuration, an omega-type piston and a methane-optimized pre-chamber, the design space was parameterized using seven geometric variables. A Sobol sequence was employed to generate 96 randomized design variants in the DoE, each evaluated through high-fidelity 3D-CFD simulations to capture key combustion and performance metrics. The resulting dataset served as the foundation for developing and evaluating several ML regression models. A rigorous ML workflow was adopted, featuring 5-fold cross-validation and hyperparameter tuning via Bayesian optimization to ensure generalization and robustness. Model selection was based on multi-metric performance criteria including prediction accuracy, error stability, and

Menaca, Rafael, Shakeel, Mohammad Raghib, Liu, Xinlei, Mohan, Balaji, AlRamadan, Abdullah, Cenker, Emre, Silva, Mickael, Zhang, Anqi, Pei, Yuanjiang, Im, Hong

Effect of Housing Design on oil Splash Lubrication in an E-Drive Unit through Computational Fluid Dynamics Simulation

2026-01-0116

4/7/2026

Effective lubrication of gears and bearings is essential for optimal performance of electric vehicle (EV) e-drive units, particularly under high-speed and high-torque conditions. Rather than relying on costly and time-consuming physical prototypes with transparent casings to study lubrication, we employed Simerics-MP+ software to create a virtual testing environment. Computational Fluid Dynamics (CFD) modeling serves as a valuable alternative by enabling rapid design assessments and shortening product development cycles. This research utilizes CFD to evaluate a housing design aimed at improving lubrication in the rear and front drive units (RDU/FDU) of EVs. Multiphase flow simulations were performed using the volume of fluid (VOF) method within Simerics-MP+, which utilizes an unstructured Cartesian mesh and handles complex mesh dynamics via volume remeshing techniques. Results demonstrated that an oil collection feature enhanced lubrication by guiding oil splash towards the bearings

Kumar, P. Madhan, Motin, Abdul, Pasunurthi, Shyam Sundar, Ganamet, Alain, Maiti, Dipak, Taghizadeh, Salar, Mohapatra, Chinmoy K.

Investigation of In-Cylinder Cycle-to-Cycle Variation Using PIV, LIF and RANS Simulation

2026-01-0299

4/7/2026

Cycle-to-cycle variation (CCV) of combustion is an issue that inevitably arises in internal combustion engines. There is a need to clarify and improve the situation, as well as predict it using computational fluid dynamics (CFD). This study involved carrying out experimental analyses of the factors that cause combustion cycle fluctuations, as well as predicting the CCV of gas flow using RANS. To elucidate the CCV in gas flow and combustion within gasoline engine, simultaneous TR-PIV, PLIF and direct-photography of flame propagation were performed using an optical single-cylinder engine, CCV prediction model for gas flow using RANS was verified. The results revealed the following: The variation in the equivalence ratio per cycle has little effect on initial combustion but does influence IMEP. Evaluating the laminar flame speed, SL and turbulent flame speed, ST as factors determining initial combustion revealed almost no correlation with SL, while moderate correlations were observed

Hokimoto, Satoshi, Moriyoshi, Yasuo, Kuboyama, Tatsuya

Advancing Oil Consumption Prediction with 3-D Multiphase CFD: Insights into Piston Design Impacts

2026-01-0282

4/7/2026

Engine oil consumption contributes to hydrocarbon and particulate emissions, catalyst degradation, and reduced thermal efficiency. Reducing it is essential for meeting emission standards and improving engine reliability. This study introduces a 3-D Computational Fluid Dynamics (CFD) framework that captures micron-scale gaps in the piston-ring-cylinder system while accounting for ring dynamics. The model leverages Simerics-MP+ features—including a novel mesh motion strategy and Mismatched Grid Interface (MGI) coupling—to resolve fine crevice regions alongside coarser bulk domains. It incorporates piston translation, ring motion, and crankshaft rotation, and uses the Volume of Fluid (VOF) method to capture multiphase interactions in thin oil films. Compared to experiments, this approach offers detailed flow visualization in optically inaccessible regions at lower cost and complexity. Unlike traditional 1-D models, it captures nonlinear behaviors without relying heavily on parameter

Mohapatra, Chinmoy K., Schlautman, Jeff, Manne, Venkata Harish Babu, Schroeder, Debera, Srinivasan, Chiranth

Fast and Robust CFD Simulation Method for Water Management in Automotive Interior Design

2026-01-0487

4/7/2026

Understanding the fluid flow behavior over and into narrow gaps is crucial for many industrial applications, particularly in the automotive sector. Evaluating the potential of water ingress into narrow pathways and towards components is of great importance to design the water management of such components. The employment of CFD simulations supports the evaluation of potential water ingress into such gaps. Lagrangian based tools are used in a variety of simulation scenarios of fluid flow, especially due to their ability to easily simulate free surfaces with strong curvatures. In our previous work, a validated simulation setup was developed using the meshless simulation tool MESHFREE from Fraunhofer ITWM [8] for simulating water entering small gaps. Especially for industrial use cases, the computation time of several days is too expensive. Thus, we enhanced this approach to a fast and robust CFD simulation that realizes industrial use cases within appropriate time. The development was

Zrnic, Dino, Konstantinovics, Athena, Kospasch, Alexander, Rugerri, Evelyn, Loy, Michael, Bäder, Dirk, Michel, Isabel

Investigation of the Blockage Phenomenon in Closed Wall Wind Tunnels during the Testing of Bluff Automotive Bodies with Small Wakes in Yawed Configurations

2026-01-0607

4/7/2026

The difficulties of testing a bluff automotive body of sufficient scale to match the on-road vehicle Reynolds number in a closed wall wind tunnel has led to many approaches being taken to adjust the resulting data for the inherent interference effects. But it has been difficult to experimentally analyze the effects that are occurring on and around the vehicle when these blockage interferences are taking place. The present study is an extension of earlier works by the authors and similarly to those studies uses the computational fluid dynamics analysis of five bodies that generate small wakes to examine the interference phenomena in solid wall wind tunnels. This focuses on the effects on the pressures, and forces experienced by the vehicle model when it is in yawed conditions up to 20 degrees. This is accomplished by executing a series of CFD configurations with varying sized cross sections from approximately 0.4% to 14% blockage enabling an approximation of free air conditions as

Gleason, Mark, Riegel, Eugen

Combustion Enhancement via Discharge Current Modulation under Turbulence Conditions

2026-01-0336

4/7/2026

Utilizing low carbon fuel in lean burn combustion presents a compelling strategy for improving thermal efficiency and reducing NOx emissions. Methane, the main content of natural gas, still receives challenge of a rapid and complete combustion process because of its low flame speed. The long combustion duration deteriorates the performance of a spark ignition engine, in terms of poor combustion instability and misfire. Although ignition timing can be utilized to adjust the combustion phasing, the ignition process faces challenges due to reduced background pressure and temperature at advanced spark timings. In this paper, a rapid compression machine equipped with a specially designed flow chamber is utilized to enhance the turbulence flow, and a custom-built ignition module is utilized to provide boosted discharge current to enhance the ignition stability under flow conditions. An effective spark energy required to enhance the combustion process is investigated under both stoichiometric

Jin, Long, Cong, Binghao, Yu, Xiao, Kong, Xiangxin, Reader, Graham, Zheng, Ming

CFD Modeling of Gas Formation and Venting During the EV’s Battery Cells Manufacturing Process

2026-01-0384

4/7/2026

The battery is a critical component of electric vehicles (EVs), where high power demands pose significant operational challenges. One such challenge is gas generation within the porous anode layer, which can lead to pressure buildup inside the battery. The complex interfacial dynamics at the microscale play a crucial role in determining the effectiveness of gas venting and the resulting pressure evolution. This study examines the effect of gas generation at two different length scales on the pressure rise and bubble dynamics. First, gas generation within a representative anode microstructure sample is investigated using a Volume of Fluid (VOF) framework that resolves tortuous flow passages. The simulations reveal that gas generation in such microstructures can lead to pressure rises of several thousand Pascals, with interfacial behavior primarily governed by surface tension effects. Second, a high-level single-cell simulation is performed using a porous media approach to evaluate

Mahyawansi, Pratik J., Schlautman, Jeff, Viswanath, Priyanka, Srinivasan, Chiranth

Machine Learning for Predicting Rotor and Brake-Fluid Temperatures in Hill-Descent Events

2026-01-0159

4/7/2026

High thermal loads on brake systems during extended descents followed by vehicle soak pose significant safety and durability risks. Excessive rotor or fluid temperatures can cause loss of braking efficacy, fluid degradation or evaporation, thermal fade, and accelerated component wear. This study uses time-history data of brake-disc and fluid temperatures which were collected during controlled hill-descent events with subsequent soak periods, where the vehicle is parked in a wind protected area. Besides the rotor and brake fluid temperatures, environmental conditions were recorded (ambient temperature, humidity, wind speed and direction) and the vehicle and brake specifications are known (rotor/caliper geometry, pad material, vehicle aerodynamic configuration and mass). 126 test runs from a dedicated vehicle program are used, each providing time-history records that form the basis of our analysis. From these records we extract phase-specific samples (descent and soak phase) and engineer

Poojari, Uday Kumar, Westphalen, Jan, Venugopal, Narayana

Time-Step Analysis of Sliding Mesh Rotation Modeling

15-19-01-0004

3/13/2026

The current work analyzes the effect of time-step size on the predictive capability and computational cost of the Sliding Mesh (SM) method for modeling flows around the rotating wheels of a mass-production luxury sport utility vehicle (SUV). Two unsteady turbulence models [Unsteady Reynolds-Averaged Navier–Stokes (URANS) and Delayed Detached Eddy Simulations (DDES)] were tested using time-step sizes ranging from the current recommended time-step size of 1 degree of rotation per time-step (1 D/TS) up to 50 degrees of rotation per time-step (50 D/TS). The flow field predictions compare favorably to the 1 D/TS case for a time-step size as large as 5 D/TS. Using this time-step size leads to a reduction in computational cost of approximately 80% for both unsteady methods. At a time-step of 5 D/TS, the computational cost of the SM method is comparable to the more commonly used Moving Reference Frame (MRF) method. However, drag and flow field predictions by the SM method at this larger time

Struk, Michael, Aultman, Matthew, Disotell, Kevin, Duan, Lian, Bianco, Antonello, Metka, Matthew, Khasdeo, Nitin

Computational Fluid Dynamic and Fatigue Analysis of Turbocharger Turbine Wheel

2026-28-0070

2/12/2026

Turbochargers are essential for improving engine efficiency by compressing air and delivering it to the engine at higher pressure, thereby increasing power output. The turbine wheel in a turbocharger operates under severe mechanical and thermal stresses, making it highly susceptible to fatigue failure, which can occur even under conditions below the rated operating load. To ensure long-term reliability, detailed analysis of the turbine’s fatigue life is essential. This study combines computational fluid dynamics with fatigue analysis to predict the performance and lifespan of a turbocharger's turbine wheel, with a focus on Inconel alloys known for their durability in extreme conditions. A numerical mesh analysis, employing 1,165,610 nodes, was conducted to achieve convergence for both temperature and stress evaluations, leading to the selection of a 2 mm mesh size. Pressure contours at the turbine-fluid interface revealed a pressure range between 1.09 and 1.05 bar, with most of the

Chelladorai, Prabhu, Balakrishnan, Navaneetha Krishnan, G, Naresh, T J, Sreejaun

CFD Simulation of Combustion and Emission Characteristics of Pure Spirulina Microalgae Biodiesel in a Single-Cylinder DI Diesel Engine

2026-28-0043

2/12/2026

In this study, the combustion and emission characteristics of a single-cylinder direct injection (DI) diesel engine fueled with Spirulina biodiesel along with diesel blends were examined using a combined CFD and thermodynamic simulation framework. Three test fuels, including pure diesel (D100), Spirulina biodiesel blends (B20 and B40), and pure Spirulina biodiesel (B100), were analysed at 1500 rpm under full load. In the first stage, CFD simulations were performed in ANSYS Fluent, where the Discrete Phase Model (DPM) was applied to capture spray atomization and droplet evaporation, while a non-premixed combustion model coupled with the RNG k-ε turbulence model was employed to resolve in-cylinder flow and heat release dynamics. Subsequently, the Diesel-RK software was utilised to predict engine performance and exhaust emissions based on compression ratios (18.5) and injection timings. Results from the CFD analysis revealed faster atomization and reduced ignition delay for biodiesel

Kumar, B Varun

Methodology for Shower Water Management in Electric Car Applications

2026-28-0068

2/12/2026

All automotive vehicles with enclosed compartments must pass the shower test standard - IS 11865 (2006). One of the most severe and critical areas of water leakage is “water entry into HVAC (heating, ventilation, and air conditioning) opening”. Excess water flow at high-pressure conditions and seepage during long-time low-pressure conditions could potentially have a significant impact on water entry inside the HVAC suction cutout given on BIW (body in white) and subsequently into the cabin. The present study clearly indicates that for making leak proof HVAC opening (suction interface), it is crucial for the structure of BIW plenum, plenum applique, and its sealing components to be robust enough to effectively collect and divert the water during rainy seasons.

Gunasekaran, Mohanraj, Namani, Prasad, Ramaraj, Rajasekar, Junankar, Ashish, Raju, Kumar

Optimized Design, Analysis, and Validation of a Tractor Muffler for Enhanced Back-Pressure Control and Cost Efficiency

2026-28-0004

2/12/2026

Internal combustion engines generate intense acoustic pulses during combustion, necessitating the use of exhaust mufflers to suppress noise emissions. With evolving regulations on permissible noise levels and the automotive industry's drive toward lightweight, high-performance vehicles, muffler designs must balance effective sound attenuation, minimal back pressure, and reduced mass. This study presents a comparative analysis of three muffler configurations serpentine, rectangular, and zigzag designed using Solid Works for a light commercial vehicle (LCV) diesel engine. The models were evaluated using computational fluid dynamics (CFD) simulations to assess their acoustic and flow performance. Each design incorporated internal baffle arrangements to enhance sound absorption while aiming to minimize back pressure. The serpentine model featured a perforated baffle layout that promoted multiple reflections and dissipated acoustic energy more efficiently. Simulation results indicated that

Deepan Kumar, Sadhasivam, Palaniselvam, Senthil Kumar, D, Ashokkumar, R, Krishnamoorthy, Mahendran, M, Pasupuleti, Thejasree, G, Dhayanithi, L, Boopalan

Numerical Study of Battery Pack Cooling for Electric Vehicles

2026-28-0110

2/12/2026

This study presents a systematic CFD-based investigation of air-cooled lithium-ion battery pack thermal management using a novel U-shaped channel. The U-shaped domain was selected due to its ability to promote recirculation and uniform air distribution, which enhances cooling effectiveness compared to conventional straight and Z-type channels. A systematic parametric optimization of inlet position and airflow velocity was performed to minimize hotspot formation and improve temperature uniformity. Results reveal that shifting the inlet from 30 mm to 20 mm and increasing velocity from 2 m/s to 3 m/s reduced the maximum battery temperature by 3.46 K, from a baseline of 333 K to 329.54 K, while maintaining minimal pressure drop. These findings highlight that strategic control of inlet parameters can yield significant thermal improvements with high cost-effectiveness and geometric simplicity.

PC, Murugan, J, Sivasankar, W, Beno Wincy, G, Arun Prasad

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