Boussinesq’s hypothesis is at the heart of eddy viscosity models, which are used in many different fields to model turbulent flows. In its present time formulation, this hypothesis corresponds to an alignment between Reynolds stress and mean strain tensors. We begin with historical remarks on Boussinesq’s results and recall that he introduced a local averaging twenty years before Reynolds, but ...

The compressible nature of the source terms in Lighthill’s acoustic analogy can be closed. For weakly compressible flows, in the absence of thermoacoustic effects, the compressibility of the source field is known in terms of solenoidal modes of the vortical flow field. In such flows, the square of the fluctuating Mach number is small and this fact, coupled with the singular nature of the acoust...

The compressible nature of the source terms in Lighthill’s acoustic analogy can be closed. For weakly compressible flows, in the absence of thermoacoustic effects, the compressibility of the source field is known in terms of solenoidal modes of the vortical flow field. In such flows, the square of the fluctuating Mach number is small and this fact, coupled with the singular nature of the acoust...

The present research numerically investigates the validity of Reynolds analogy for micro-convective water flow between Stanton number (St) and Fanning friction factor (ff), taking into account combined fluid properties variations such as temperature-dependent density, viscosity, thermal conductivity. is suggested to be valid when St increases thermophysical (TFP) with a decrease in ff. This ana...

Introduction Boundary layer development in supersonic The intended application for this study is to further the understanding of the flow reacting flows is not well understood. A new capability has been developed which makes through the combustor of a scramjet (supermore extensive surface measurements practisonic combustion ramjet) engine. Experical, leading to an increased understanding of men...

In this paper, the relation between skin friction and heat transfer along windward sides of blunt-nosed bodies in hypersonic flows is investigated. The self-similar boundary layer analysis is accepted to figure out the distribution of the ratio of skin friction to heat transfer coefficients along the wall. It is theoretically obtained that the ratio depends linearly on the local slope angle of ...

We point out some similarities between the statistics of high Reynolds number turbulence and critical phenomena. An analogy is developed for two-dimensional decaying flows, in particular by studying the scaling properties of the two-point vorticity correlation function within a simple phenomenological framework. The inverse of the Reynolds number is the analog of the small parameter that separa...

We investigate the Reynolds analogy over riblets, namely between fractional increase in Stanton number $C_h$ and skin-friction coefficient $C_f$ , relative to a smooth surface. direct numerical simulation data of Endrikat et al. ( Flow Turbul. Combust. vol. 107, 2021, pp. 1–29). The riblet groove shapes are isosceles triangles with tip angles $\alpha = {30}^{\circ }, {60}^{\circ {90}^{\circ }$ ...