A non-isotropic vorticity dyadic tensor (VDT) sub-grid scale model is developed. Based on the direct numerical simulation database of channel turbulence, the sub-grid scale energy dissipation of the model in wall-bounded turbulence is studied, and a wall damping function for VDT model is developed. The sub-grid scale energy dissipation produced by the wall-corrected VDT model is more accurate than that of the Smagorinsky model with Van Driest damping and the dynamic Smagorinsky model.

The low-frequency pressure pulsations in a large low-speed open jet wind tunnel were studied using a 1:20 scaled model wind tunnel. It was found that plane pressure standing waves existed in all three directions of the wind tunnel’s plenum. It was confirmed that the large pressure pulsations in the transverse direction of the plenum were caused by the resonance of the plane pressure standing waves in that direction with the edgetone feedback (vortex-sound feedback between the nozzle and the collector). The analysis of the standing waves in the vertical direction of the plenum suggested that they might come from self-excited oscillations. For the model wind tunnel with a 1:20 strictly scaled collector, the standing waves in the transverse direction of the plenum were much stronger than those in the other two directions. By increasing the width of the collector, the intensity of the standing waves in the transverse direction was significantly reduced to a level similar to that of the standing waves in the vertical direction. It was also found that the standing waves in the transverse direction were significantly enhanced after a floor was added to the test section.

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