Assessment of the Reliability of CFD simulations for Delta wings Using Visualization Post Processings

Vortical flows over a strake delta are numerically simulated for the assessment of the reliability of the numerical simulations. The results of the laminar flows show that the computed surface pressure distributions do not agree with the experiment. Several parameters that might cause the discrepancy of the surface pressure distributions are examined. The grid resolution has large influence on the characteristics of the primary vortex and even 4 million grid points are not sufficient. The discrepancy in the location and the strength of the secondary vortex, which influences the location and the strength of the primary vortex leads to inaccurate prediction of the vortical flows especially on the strake-delta wing. The turbulent flow simulations show better agreement with the experiment. The results indicate that better turbulence model with a high accurate scheme is required. Flow visualization is intensively used for the analysis of the flow fields. The visualization tools are inevitable for the assessment of the reliability of the CFD simulations as the surface data is not necessarily sufficient for us to understand the flow field.