The vertical flux of geopotential and the conversion between eddy available potential and eddy kinetic energy due t o non-stationary disturbances are studied by solving numerically the diagnostic as well as the prognostic equations of a linearized 20-level model. The vertical distribution of these quantities thus computed compares well with those obtained by other authors from observed data and...

We consider a prototypical problem: simulate velocity and pressure in a turbulent flow using large eddy simulation (LES) and then use the results to estimate the force the underlying turbulent flow exerts on an immersed body. For eddy viscosity-type LES models we develop the appropriate continuous sensitivity equation and show how it can improve the functional estimate by using the sensitivity ...

The variational multiscale method is applied to the large eddy simulation ~LES! of homogeneous, isotropic flows and compared with the classical Smagorinsky model, the dynamic Smagorinsky model, and direct numerical simulation ~DNS! data. Overall, the multiscale method is in better agreement with the DNS data than both the Smagorinsky model and the dynamic Smagorinsky model. The results are some...

Large-eddy simulation of particle-laden turbulent channel flow is investigated for several subgrid models and Stokes numbers with the objective to investigate the accuracy of the subgrid models studied with respect to particle behavior. It is shown that the wall-normal particle velocity and particle velocity fluctuations are reduced compared to DNS, if the filtered fluid velocity calculated in ...

A fully developed square channel flow with a Reynolds number of Re = 4410 (based on bulk velocity and duct width) has been calculated using Large Eddy Simulation (LES) technique with the Smagorinsky eddy viscosity model. Results for the Prandtl’s secondary motion which is turbulence-driven show good qualitative picture and are in good quantitative agreement with values from other authors. Diffe...

A dynamic eddy viscosity (DEV) model and a constant (CEV) are proposed for stabilizing the temporal direct deconvolution (TDDM) in large-eddy simulation of turbulence. Compared to original unresolved subfilter-scale used TDDM, new models reduce number empirical coefficients make TDDM more convenient be applied practice. The DEV does not have any coefficients, CEV has only one coefficient that i...

Large-eddy simulation (LES) has become a widely-used method for computation of field-scale environmental flows; however, challenges remain in determining the optimal turbulence closure method. Recently, the concept of explicit filtering and reconstruction has become recognized as a means to obtain more accurate simulation results (Carati et al. 2001, Winckelmans et al. 2001, Stolz et al. 2001, ...

The efficacy of large-eddy simulation ~LES! with wall modeling for complex turbulent flows is assessed by considering turbulent boundary-layer flows past an asymmetric trailing-edge. Wall models based on turbulent boundary-layer equations and their simpler variants are employed to compute the instantaneous wall shear stress, which is used as approximate boundary conditions for the LES. It is de...