Direct numerical simulation (DNS) is performed to examine laminar to turbulent transition due to high-frequency secondary instability of stationary crossflow vortices in a subsonic swept-wing boundary layer for a realistic natural-laminar-flow airfoil configuration. The secondary instability is introduced via inflow forcing derived from a two-dimensional, partial-differential-equation based eig...

This article presents a comparison of the entropy production in a laminar and transitional boundary layer flow with the spectral entropy produced in a region of instability induced by an imposed periodic disturbance. The objective of the study is exploratory in nature by computing a boundary-layer environment with well-established computer techniques and comparing the predictions of the maximum...

The intent of this analysis is to explore the influence of thermal radiation paired with variable thermal conductivity on MHD micropolar fluid flow over an upper surface. The novelty of the present model is to consider the fluid flow along an upper horizontal surface of a paraboloid of revolution (uhspr) with the porous medium.  This physical phenomenon is described by a set of coupled...

In this paper, we investigate the similarity solutions for a steady laminar incompressible boundary layer equations governing the magnetohydrodynamic (MHD) flow near the forward stagnation point of two-dimensional and axisymmetric bodies. This leads to the study of a boundary value problem involving a third order autonomous ordinary differential equation. Our main results are the existence, uni...

A variable-porosity suction glove has been flown on the F-16XL-2 aircraft to demonstrate the feasibility of this technology for the proposed High-Speed Civil Transport. Boundary-layer transition data on the titanium glove primarily have been obtained at speeds of Mach 2.0 and altitudes of 15,240–16,764 m (50,000–55,000 ft). The objectives of this flight experiment have been to achieve 0.50–0.60...

This study considers the convective instability of a water-filled shallow wedge with an absorptive bottom subject to solar radiation. Previous studies have revealed that a thermal boundary layer develops along the sloping bottom due to the absorption of penetrative radiation there, and this boundary layer is potentially unstable to the Rayleigh–Bénard instability. The stability properties of th...

A modeling procedure is developed for natural convection heat transfer from an isothermal heated sphere located at the center of an isothermal, cooled, sphericalshaped enclosure. The model is based on the linear superposition of conduction and convection solutions, where the convective component is determined based on a combination of two limiting cases, laminar boundary layer convection and tr...

Future rocket-nozzle extensions have to be thermally protected by a film of cooling gas. The hot supersonic boundary-layer flow may be fully turbulent despite a strong favorable pressure gradient and strongly cooled walls. In contrast to previous investigations, where a laminar boundary-layer state was considered, the present work deals with the effects of a turbulent flow. The cooling film is ...