Modified Spalart-Allmaras one-equation turbulence model for rough wall boundary layers

The objective of the study was to develop a transport equation type turbulent model for boundary layer flows over rough surfaces by modifying the Spalart-Allmaras (S-A) one-equation turbulent model. The modified S-A turbulence model was evaluated against experimental data for flows developing over acoustically treated rough surfaces with varying surface roughness, freestream velocity, and pressure gradient conditions. The modeling approach proposed here should enable the three-dimensional Navier-Stokes analysis of inlets and nozzles with allowance for roughness effects for more accurate performance predictions. (AIAA)