Natural grid stretching for DNS of wall-bounded flows

Adaptation of Structured Grid for Supersonic and Transonic Flows

Two distinct redistribution grids - adaptation techniques, spring analogy and elliptic grid generator are applied to two-dimensional steady, inviscid, shocked flows, and the ability of each technique is examined and compared. Euler equations are solved base on Roe's Reimann solver approach to simulate supersonic flow around a sphere, transonic flow about an airfoil and supersonic flow in a symm...

Weak Dirichlet Boundary Conditions for Wall-Bounded Turbulent Flows

In turbulence applications, strongly imposed no-slip conditions often lead to inaccurate mean flow quantities for coarse boundary-layer meshes. To circumvent this shortcoming, weakly imposed Dirichlet boundary conditions for fluid dynamics were recently introduced in [4]. In the present work, we propose a modification of the original weak boundary condition formulation that consistently incorpo...

A new eddy-based model for wall-bounded turbulent flows

A Vortex Method for Wall Bounded Turbulent Flows

Turbulent ow in a channel is simulated using a vortex method. Smoothed vortex sheets cover the near wall region while the vorticity in the remainder of the ow is contained in convecting and stretching vortex laments. The sheet elements are convected and regridded at each time step thus enabling evaluation of their wall-normal viscous diiusion and vortex stretching using nite diierences. New lam...

Geometry of turbulence in wall-bounded shear flows: periodic orbits

The dynamical theory of moderate Reynolds number turbulence triangulates the infinite-dimensional Navier-Stokes state space by sets of exact solutions (equilibria, relative equilibria, periodic orbits, ...) which form a rigid backbone which enables us to describe and predict the sinuous motions of a turbulent fluid. We report determination of a set of unstable periodic orbits from close recurre...