Turbulence behind 3D multi-scale sparse grids

A fundamentally new idea in grid generated turbulence is the 3D Sparse Grid (3DS) concept [N. A. Malik. Sparse 3D Multi-Scale Grid Turbulence Generator. US Patent No. US 9,599,269 B2 (2017)] which reduces the effective blockage ratio compared to the 2D flat fractal grids, s 3DS Lt s 2DF , and possess a much greater parameter space which could allow further optimization of the turbulence as compared to the 2D fractal (2DF) grids. Here, we report on some theoretical results regarding blockage ratio reduction in a 3-frame 3DS system, and some results from Direct Numerical Simulations comparing the turbulence characteristics generated by 3DS with Regular (RG) and 2DF grids cases.