A vertical two-dimensional morphodynamic model with non-hydrostatic, free surface flow is reported herein. This numerical model can simulate flow and turbulence characteristics over sand waves. Likewise, model can reproduce the sand wave formation and migration process as well as free surface oscillation simultaneously in a moving boundary domain with the implication of a generalized coordinate...

Within the framework of theory unsteady turbulent flows in a stratified fluid, new parameterization Prandtl number is proposed. The included k-ε-closure and used within three-dimensional model thermohydrodynamics an enclosed water body where density distribution includes pycnocline. This allows us to describe turbulence shear flow without restrictions associated with gradient Richardson justify...

The present investigation concerns the development of advanced scalar turbulence modeling approaches and their application to the calculation of non-isothermal wall-bounded flow phenomena. A new scalar modeling technique based on scalar turbulent scales is proposed and implemented at a second-order modeling approach. Instead of the classical analogy concept between the mechanical and the scalar...

UNLABELLED Accurate prediction of ventilation flow is of primary importance for designing a healthy, comfortable, and energy-efficient indoor environment. Since the 1970s, the use of computational fluid dynamics (CFD) has increased tremendously, and nowadays, it is one of the primary methods to assess ventilation flow in buildings. The most commonly used numerical approach consists of solving t...

Manoeuvring underwater vehicles experience complex three dimensional flow. Features include stagnation and boundary layer separation along a convex surface. The resulting free vortex sheet rolls up to form a pair of streamwise body vortices. The track and strength of the body vortex pair results in a nonlinear increase in lift with as body incidence increases. Consequently, accurate capture of ...

Different variants for buoyancy-affected terms in k-ε turbulence model have been utilized to predict the flow parameters more accurately, and investigate applicability of alternative k-ε turbulence buoyant closures in numerical simulation of a horizontal gravity current. The additional non-isotropic turbulent stress due to buoyancy has been considered in production term, based on Algebraic Stre...

A non-premixed coaxial oxy-fuel turbulent flame was studied numerically with standard and realizable k-ε turbulence model and a comparison was made between them. The governing equations were solved by finite volume approach and were discretized using the second order upwind scheme. The presumed β-PDF model was applied to model turbulence-combustion interaction. The discrete ordinate radiation h...

A comparative assessment is done on the effectiveness of some developed and reported macroscopic and mesoscopic models deployed for addressing the three-dimensional thermo-fluidic transport during high-power laser surface alloying process. The macroscopic models include the most celebrated k–ε turbulence model and the large eddy simulation (LES) model, whereas a kinetic theory-based lattice Bol...

A simple kinematically consistent expression for the longitudinal two-point correlation function related to both the integral length scale and the Taylor microscale is obtained. On the inner scale, in a region of width inversely proportional to the turbulent Reynolds number, the function has the appropriate curvature at the origin. The expression for two-point correlation is related to the nonl...

Numerical simulations of the gas-liquid bubbly flow in a bubble column were conducted with the commercial CFD package CFX-4.4 to investigate the performance of three models (Pfleger and Becker, 2001; Sato and Sekoguchi, 1975; Troshko and Hassan, 2001) to account for the bubble-induced turbulence in the k-ε model. Furthermore, the effect of two different interfacial closure models was investigat...