Achievement of a good performance in a Direct Numerical Simulation (DNS) of a particulate flow has been restricted to a low particle Reynolds number below a few hundreds due to the limitation of computational load by using a fine grid (Harada and Gotoh, 2008). Hence, in this study, to perform numerical simulations in higher particle Reynolds numbers, a Large Eddy Simulation (LES) by Smagorinsky...

Large Eddy Simulation (LES) and Direct numerical Simulation (DNS) of polydisperse evaporating sprays with Eulerian models are promising tools for high performance computing of combustion applications. However, the spray system of conservation equations has a convective part which is similar either to general gas dynamics (GGD) Euler equations with a real gas type state law or to the pressureles...

Nowadays there are wide possibilities to perform numerical studies of turbulent natural convection flows on the base of 3D unsteady formulations [1]. Direct Numerical Simulation (DNS) is the most attractive and reliable approach for getting a detailed knowledge on convection [2, 3]. However, DNS applications are practically limited by the case of simplified geometry and/or the Rayleigh numbers ...

[1] We describe three-dimensional direct numerical simulations (DNS) of double-diffusively stratified flow interacting with inflectional shear. The extreme difference in diffusivity (and thus minimum length scale) between heat, salt and momentum in seawater is replicated for the first time in a three-dimensional simulation. The primary instability generates salt sheets, which are oriented paral...

Spray combustion is encountered in many engineering applications, such as internal combustion engines and gas-turbine aircraft engines. In these systems, the concurrent processes of liquid atomization, droplet evaporation, turbulent dispersion, and combustion interact and strongly affect each other, which makes experimental measurement and high-fidelity simulation challenging. To understand the...

A combined modeling and experimental study of acoustic cavitation bubbles that are initiated by focused ultrasound waves is reported. Focused ultrasound waves of frequency 335 kHz and peak negative pressure 8 MPa are generated in a water tank by a piezoelectric transducer to initiate cavitation. The resulting pressure field is obtained by direct numerical simulation (DNS) and used to simulate s...

In this paper we will present the results of direct numerical simulation (DNS) of the flow over a small amplitude wavy wall. The evolution in space and time of particles are released in this flow will be examined. It will be shown that small waves on the channel bottom can generate large longitudinal vortices similar to Langmuir vortices that are observed in flows with waves at the free-surface...

An overview and examples of the application of Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) to prediction and the scientific study of dispersed, turbulent two-phase flows is presented. This contribution focuses on Eulerian-Lagrangian treatments in which dispersed phase properties are obtained from discrete particle trajectories. The scope of the approaches considered are on...

A steady Ekman layer with a thermally stratified outer flow and an adiabatic boundary condition at the lower wall is studied using direct numerical simulation (DNS) and large eddy simulation (LES). An initially linear temperature profile is mixed by turbulence near the wall, and a stable thermocline forms above the mixed layer. The thickness of the mixed layer is reduced by the outer layer stra...

We present a direct numerical simulation (DNS) study of buoyancy-driven bubbly flows in the presence large-scale driving that generates turbulence. On increasing turbulence intensity: ( ) bubble trajectories become more curved and b average rise velocity bubbles decreases. find energy spectrum flow shows pseudo-turbulence scaling for length scales smaller than diameter Kolmogorov larger diamete...