Low Speed Wind Tunnel Flow Diagnostics and Benchmark Cases for Thermal Fluids CFD Validation Efforts

Abstract

A low speed, closed loop wind tunnel at Texas A&M University is presented for the study of turbulent mixing produced by a variety of flows types. Anticipated experiments range from canonical “unit flows” to more complex combinations of flows and geometries. Originally located at the University of Pittsburgh, the facility has since been re-located to the Thermal Hydraulics Verification and Validation (THVV) laboratory at Texas A&M University. The tunnel has undergone considerable modification and updated diagnostics prompting renewed interest in flow quality assessment. This includes a thorough mapping of the tunnel inlet velocity profile provided by Particle Image Velocimetry (PIV) measurements. Additional temperature and gage pressure measurements complete the assessment of system capabilities. These preliminary diagnostics yield empirically determined boundary conditions and fluid property correlations necessary for Computational Fluid Dynamics (CFD) model validation. The article concludes with the presentation of two unit flow types, including flow past a cylinder, with three distinct cross sections, and a single round jet in cross flow at three velocity ratios. The unit flows serve as initial benchmarks for THVV simulation efforts. Key validation metrics are presented for each benchmark including ensemble averaged velocities, Reynolds stresses, and proper orthogonal decomposition (POD) eigenvectors.