Multi-Modal Conversion of a Boundary-Layer Wind Tunnel to Open-Jet Test Cell

A low-speed, open-circuit wind tunnel at Youngstown State University has been converted to a multi-modal facility, enabling interchangeable configurations from boundary-layer test section to an open-jet test cell to support flexible capabilities for ground and air vehicle technology development. The existing test-section entrance geometry of 0.24- by 1.0-m (internal flow configuration) was converted to a 0.50- by 0.50-m cross-section (external flow configuration), making use of the commonality of upstream flow conditioning components. Redistribution of the contraction exit area from the internal flow configuration enables the facility to maintain the same maximum test speed between the two modes. Reynolds-Averaged Navier-Stokes (RANS) calculations of the flow in the new three-dimensional contraction section and evolution of the free jet in the test cell are reported from the design study phase to assess boundary-layer separation margin and modeled plane jet spreading rate. Flow characterizations of the modified facility are reported, which include mean velocity measurements from a Pitot-tube survey and a hot-wire anemometer for turbulent velocity fluctuations. Cross-sectional uniformity and turbulence intensity are compared between the two configuration modes. The multi-modal facility offers flexible advantages in research-grade testing for air-cooled thermal management systems for electrified propulsion, testing of smart controls and materials under air load, and noise/vibration/harshness testing for advanced ground and air mobility components.