A problem of great concern in aviation and submarine propulsion is the control of the boundary layer and, in particular, the methods to extend the laminar region as a means to decrease noise and fuel consumption. In this paper we study the flow of air along an airfoil when a layer of ionized gas and a longitudinal electric field are created in the boundary layer region. By deriving scaling solu...

Chemical and aerosol processes in the transition from closedto open-cell circulation in the remote, cloudy marine boundary layer are explored. It has previously been shown that precipitation can initiate a transition from the closedto the open-cellular state, but that the boundary layer cannot maintain this open-cell state without a resupply of cloud condensation nuclei (CCN). Potential sources...

in the age of technology, it is vital to cool down different parts of a device to use it more beneficially. using nanofluids is one of the most common methods which has shown very effective results. in this paper, we have rephrased a classic equation in fluid mechanics, i.e. the falkner-skan boundary layer equation, in order to be used for nanofluid. this nonlinear equation, which was presented...

Laminar-turbulent transition is an important feature in aerospace aerodynamics because of its influence on fuel consumption via the drag. Despite many years of research on fundamental mechanisms of the transition process in many generic configurations relevant for aircrafts, as well as other applications, there are situations which are less well understood and hence much more difficult to predi...

We study the inviscid limit problem of the incompressible flows in the presence of both impermeable regular boundaries and a hypersurface transversal to the boundary across which the inviscid flow has a discontinuity jump. In the former case, boundary layers have been introduced by Prandtl as correctors near the boundary between the inviscid and viscous flows. In the latter case, the viscosity ...

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...

This paper performs Direct Numerical Simulation of transition induced by blowing and suction in a spatially evolving Mach 2.25 supersonic boundary layer. We use a novel algorithm (Park & Mahesh 2007) capable of solving compressible flow on unstructured grids. Our objective is to evaluate our unstructured capability to simulate supersonic transition. Transition is achieved using controlled perio...

This paper details a joint numerical and experimental effort to investigate a transition process in a laminar separation bubble, with the emphasis being put on the numerical contribution. A laminar separation bubble is formed if a laminar boundary layer separates in a region of adverse pressure gradient on a flat plate and undergoes transition, leading to a reattached turbulent boundary layer. ...

The results of the computation of entropy generation rates through the dissipation of ordered regions within selected helium boundary layer flows are presented. Entropy generation rates in helium boundary layer flows for five cases of increasing temperature and pressure are considered. The basic format of a turbulent spot is used as the flow model. Statistical processing of the time-dependent s...

A conditional sampling based on the combination of a passive tracer emitted at the surface and thermodynamic variables is proposed to characterise organized structures in large-eddy simulations of cloud-free and cloudy boundary layers. The sampling is evaluated against more traditional sampling of dry thermals or clouds. It enables the characterization of convective updrafts from the surface to...