We demonstrate, via simulations of asymptotically reduced equations describing rotationally constrained Rayleigh-Bénard convection, that the efficiency of turbulent motion in the fluid bulk limits overall heat transport and determines the scaling of the nondimensional Nusselt number Nu with the Rayleigh number Ra, the Ekman number E, and the Prandtl number σ. For E << 1 inviscid scaling theory ...

Direct numerical simulation (DNS) is used to study laminar to turbulent transition induced by a discrete hemispherical roughness element in a high-speed laminar boundary layer. The simulations are performed under conditions matching the experiments of Danehy et al. (AIAA Paper 2009–394, 2009) for free-stream Mach numbers of 3.37, 5.26 and 8.23. It is observed that the Mach 8.23 flow remains lam...

The problem of laminar, natural convection flow over a vertical f rus tum of a cone is treated in this paper. The thermal boundary condition at the wall include both the constant wall temperature and the constant wall heat flux cases. The governing differential equations are solved by a combinat ion of quasilinearization and finitedifference methods. Numerical solutions are obtained for a range...

fluids for various industrial applications because of their excellent thermal performance. This study analytically and experimentally examines the effects of nanoparticle dispersion on the entropy generation of EG–Al2O3 ...

An oscillatory, zero-net-mass flux Jet and Vortex Actuator (JaVA) was modelled as part of a flat plate and simulated in a boundary layer flow. JaVA is an active flow control device that can be used for flow separation control and thus can delay boundary layer transition. It has been already shown experimentally that JaVA induced flow types in still water include angled and vertical jets, wall j...

The present work introduces a modified scheme for the solution of compressible 2-D full Navier-Stokes equations, using Flux Vector Splitting method. As a result of this modification, numerical diffusion is reduced. The computer code which is developed based on this algorithm can be used easily and accurately to analyze complex flow fields with discontinuity in properties, in cases such as shock...

The thermal damping of a dynamic vibrating micromirror is an important factor affecting the design of MEMS based actuator systems. In the development process of new micromirror systems, assessing the extent of energy loss due to thermal damping accurately and predicting the performance of the system is very essential. In this paper, the depth of the thermal penetration layer at different eigenf...

*Correspondence: Rachel Honnert, Centre National de Recherches Météorologiques, Groupe d’Etudes de l’Atmophère Météorologique, Météo France/CNRS, GMAP 42, avenue Gaspard Coriolis, 31100 Toulouse, France e-mail: [email protected] In numerical weather prediction (NWP) models, at mesoscale, the sub-grid convective boundary-layer turbulence is dominated by the uni-dimensional (1D) vertical th...

Roughness elements in high speed flows can cause laminar-turbulent transition leading to higher heating rates and drag. Transition of flow past a hemispherical bump placed on a flat plate is explored in this paper for three Mach numbers [3.37, 5.26, 8.23] using direct numerical simulation on unstructured grids. The simulation parameters are chosen to match the experiments carried out by Danehy ...