The unsteady Navier{Stokes equations ooer a large variety of instantaneous solutions even for rather simple boundary conditions once the relevant spatial and temporal scales of the problem at hand are adequately resolved. This is especially true for DNS (Direct Numerical Simulation) of laminar-turbulent transition, where an initially lam-inar ow, disturbed by some unsteady uctuations \breaks do...

A numerical simulation has been performed of the disturbed flow through and over a twodimensional array of rectangular buildings immersed in a neutrally stratified deep roughwalled turbulent boundary-layer flow. The model used for the simulation was the steady-state Reynolds-averaged Navier-Stokes equations with linear and non-linear eddy viscosity formulations for the Reynolds stresses. The ed...

593 The region downstream of a supercritical collisionless shock, the magnetosheath (MSH), is known to be in a highly disturbed turbulent state [1–3]. The undisturbed solar wind (SW) streams with supermagnetosonic velocity V > c ms at a magnetosonic Mach number up to M ms ~ 15. At the Earth’s bow shock (BS), the SW decelerates to Mach numbers M ms < 1, thermalizes, and, when entering the MSH, i...

turbulent fluxes in the atmospheric boundary layer are calculated using different models. one of the most popular and operational models in this groundwork is the second order turbulent model of mellor and yamada that has been widely used to simulate the planetary boundary layer (pbl). despite its popularity, it has been shown that this model has several weeknesses that affect its accuracy. the...

Turbulent flow over an array of wall-mounted cubic obstacles has been numerically investigated using large-eddy simulation. The simulations have been performed using high-performance computations with local cluster systems. The array of cubes are fully submerged in a simulated deep rough-wall atmospheric boundary-layer with high turbulence intensity characteristics of environmental turbulent fl...

Data from the near-wall region of an attached and a separated turbulent boundary layer are used for the development of near-wall damping functions utilized in turbulence modelling. The model considered is an explicit algebraic Rey-nolds stress model. The data are taken from two direct numerical simulations. The turbulent boundary layer equation is analyzed in order to extend the validity of exi...

mixed convection is a fundamentally significant heat transfer mechanism that occurs in selection industrial and technological applications. in this study, first the laminar mixed convection inside rectangular enclosure with moving wall and aspect ratio=10 is modeled and then the results are compared with other investigate. after showing varity of results, the investigation is continued with tur...

A novel numerical scheme has been developed to simulate high speed viscous flows in complex geometries using unstructured grids. A characteristic–filter based shock capturing scheme is applied as a corrector step to a non–dissipative predictor scheme. This algorithm is being used to study shock turbulent boundary layer interactions and this paper presents the results of a turbulent flow at Mach...

Two observations drawn from a thoroughly validated direct numerical simulation of the canonical spatially developing, zero-pressure gradient, smooth, flat-plate boundary layer are presented here. The first is that, for bypass transition in the narrow sense defined herein, we found that the transitional-turbulent spot inception mechanism is analogous to the secondary instability of boundary-laye...