To better understand the vortex dynamics of coherent structures in turbulent and transitional bound ary layers we consider direct numerical simulation of the interaction between a at plate boundary layer ow and an isolated hemispherical roughness element Of principal interest is the evolution of hairpin vortices that form an interlacing pattern in the wake of the hemisphere lift away from the w...

We consider the approximation of the frequency domain three dimensional Maxwell scattering problem using a truncated domain perfectly matched layer (PML) (cf. [1] and [2]). We also treat the time-harmonic PML approximation to the acoustic scattering problem. Following [3], a transitional layer based on spherical geometry is defined which results in a constant coefficient problem outside the tra...

Abstract Understanding the generation mechanism of heat flux is essential for design hypersonic vehicles. We proposed a novel formula to decompose coefficient into contributions different terms by integrating conservative equation total energy. The reliability well demonstrated direct numerical simulation results transitional boundary layer. Through this formula, exact process energy transport ...

Experiments were performed in the T5 Hypervelocity Shock Tunnel to investigate nonequilibrium real-gas effects on separation length using a double-wedge geometry and nitrogen test gas. Local external flow conditions were estimated by computing the inviscid nonequilibrium flow field. A new scaling parameter was developed to approximately account for wall temperature effects on separation length ...

high weissenberg boundary layer flow of viscoelastic fluids on a stretching surface has been studied. the flow is considered to be steady and two dimensional. flows of viscoelastic liquids at high weissenberg number exhibit stress boundary layers near walls. these boundary layers are caused by the memory of the fluid. upon proper scaling and by means of an exact similarity transformation, the n...

In this paper, an effective procedure based on coordinate stretching and radial basis functions (RBFs) collocation method is applied to solve singularly perturbed differential-difference equations with layer behavior. It is well known that if the boundary layer is very small, for good resolution of the numerical solution at least one of the collocation points must lie in the boundary layer. In ...

the flow characteristics around an elliptic cylinder with an axis ratio of ar=2 located near a flat plate were investigated experimentally. the elliptic cylinder was located on the inside and outside a turbulent boundary layer region whose thickness (δ) is 0.38b. the reynolds numbers based on the height of the cylinder cross-section were 15000 and 30000. measurements of mean velocity and turbul...

this paper studied the mathematical method of flow with regard to two-phase boundary layer that created over the iced surface. based on experimental results, skin drag over the iced surface compared with this force that compute with slip condition. based on this results, for iced surface blasius equation solving at non-slip condition, can replace with solving the blasius equation with slip cond...