Top-Down, Bottom-Up Diffusion Experiments in a Water Convection Tank

摘要: Abstract Large-eddy simulation (LES) results indicate that turbulent scalar diffusion in the convective atmospheric boundary layer (CBL) has interesting properties. A introduced into bottom of CBL with no flux through top (bottom-up diffusion) a radically different eddy diffusivity profile than at zero surface (top-down diffusion). To test these LES results, set experiments was designed and carried out replica original Deardorff-Willis laboratory convection tank. The authors measured mean gradients inferred profiles for two scalars, temperature, dye concentration. Using data, vertical top-down, bottom-up gradient functions diffusivities are calculated. Experimental good agreement predictions.