This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Some Basic Investigations into the Principles of Ground Simulation Techniques in Automotive Wind Tunnels
Annotation ability available
Sector:
Language:
English
Abstract
With the help of theoretical considerations it is shown that the flow between a car and the ground is of boundary layer type, as long as there is no recirculation. Thus, boundary layer theory can be applied to evaluate the order of magnitude of typical effects like displacement and momentum-loss thicknesses of ground-plane boundary layer. If the boundary layer in a wind tunnel with stationary ground is to be controlled, either by distributed suction or by tangential blowing, to simulate on-road conditions, boundary layer theory can provide the orders of magnitude of modifications that have to be applied. Experiments with a ground-effect quarter-scale car with ground simulation by distributed suction and moving belt showed coincidence with theoretical predictions concerning the required suction rate, if integral coefficients (eg CD, CL) of both flow cases are matched. Since the flow was recirculating over the moving belt however, there were significant physical differences compared to ground simulation by boundary layer suction along a stationary ground. Such types of flows can only be created with the help of tangential blowing, as long as a stationary ground plane is to be used. For the ground-effect as well as for a typical passenger car, there was a fairly small sensitivity of the integral quantities to oversuction.
Recommended Content
Citation
Wiedemann, J., "Some Basic Investigations into the Principles of Ground Simulation Techniques in Automotive Wind Tunnels," SAE Technical Paper 890369, 1989, https://doi.org/10.4271/890369.Also In
References
- SCHULZ V. HAUSMANN, F.K VAGT, J.D. Influence of Test-Section Length and Collector Area on Measurements in 3/4-Open-Jet Automotive Wind Tunnels SAE Paper 880251 Detroit 1988
- FRITZ, W. Two Dimensional Euler and Navier Stokes Solutions of Flow over the Mid Section of a Car Second IAVD Congress Geneva 1985
- HACKETT, J.E. WILLIAMS, J.E. BAKER, J.B. WALLIS, S.B. On the Influence of Ground Movement and Wheel Rotation in Tests on Modern Car Shapes SAE Paper 870245 Detroit 1987
- STAPLEFORD, R. CARR, G.W. Aerodynamic Characteristics of Exposed Rotating Wheels MIRA Report No. 1970/02 1970
- JANSSEN, L.J. MÜLLENBACH, P. DEUTENBACH, K.R. The Effect of Ground Simulation in Wind Tunnel Testing with Cars 6 th Colloquium on Industrial Aerodynamics, Road-Vehicle-Aerodynamics Aachen June 19-21 1985
- BEESE, E. Untersuchungen zum Einfluß der Reynolds-Zahl auf die aerodynamischen Beiwerte von Tragflügelprof ilen in Bodennähe Dissertation Fakultät für Maschi-nenbau, Ruhr- Universität Bochum 1982
- VAN DYKE, M. Perturbation Methods in Fluid Mechanics Academic Press New York and London 1964
- BERNDTSSON, A. ECKERT, W.T. MERCKER, E. The Effect of Ground-plane Boundary Layer Control on Automotive Testing in a Wind Tunnel SAE Paper 880248 Detroit 1988
- GOLDSTEIN, S. On Laminar Boundary-Layer Flow Near a Position of Separation Quart. J. Mech. Appl. Math. 1 43 69 1948
- HUCHO, W.H. JANSSEN, L.J. SCHWARZ, G. The Wind Tunnel's Ground Plane Boundary Layer - its Interference with the Flow Underneath Cars SAE Paper 750066 Detroit 1975
- SCHLICHTING, H. Boundary-Layer Theory Seventh McGraw-Hill New York 1979
- WIEDEMANN, J. Der Einfluß von Ausblasen und Absaugen an durchlässigen Wänden auf Strömungen bei großen Reynoldszahlen Dissertation Fakultät für Maschinenbau, Ruhr-Universität Bochum 1983
- WULF, R. Bodensimulationsplatte mit Grenzschichtabsaugung DFVLR Report No. IB 157-75 A 05 1975
- TELIONIS, P.D. Unsteady Viscous Flows Springer Verlag New York 1981
- HACKETT, J.E. BOLES, R.A. Moving-Ground Simulation by Tangential Blowing J. Aircraft 16 12 December 1979
- WIEDEMANN, J. Theoretical and Experimental Optimization of the Road-Vehicle Internal Flow Von Karman Institute Rhode-St.-Genese (Belgium) March 17.-21 1986
- SOJA, H. WIEDEMANN, J. The Interference Between Exterior and Interior Flow on Road Vehicles. Societe des Ingenieurs de l'Automobile (S.I.A.) Journee d'etude: Dynamique du Vehicule - Securite Active June 16-17 1987