Numerical Simulation of Vortical Flows Over a Strake-Delta Wing
Computations of vortical flows over a strake-delta wing are carried out using the three-dimensional, thin-layer Navier-Stokes equations at a low Mach number. A fine-mesh distribution with 850,000 grid points is used to capture the physical phenomenon, and computations are carried out for angles of attack from 6-40 deg. Over this range of angle of attack, the computed lift coefficients are in good agreement with the experimental data. A computed result at a = 12 deg shows the interaction process of the vortex emanating from the leading edge of the strake with that from the leading edge of the wing. The computation at a = 30 deg indicates that bubble-type vortex breakdown occurs near the trailing edge of the wing, whereas at a = 35 deg, the spiral type of vortex breakdown occurs. An intensive study using sophisticated graphics programs reveals some features of the breakdown phenomenon. Comparison of the computed results with those of the experiment shows that qualitative features of the flow are well simulated when using a fine mesh. The result also indicates the importance of the grid resolution in simulating vortical flows. Still better resolution is necessary to obtain better quantitative results for this complicated flowfield.