We investigate the dynamical and statistical features of turbulent Taylor–Couette flow (for a radius ratio 0.5) through three-dimensional direct numerical simulations (DNS) at Reynolds numbers ranging from 1000 to 8000. We show that in three-dimensional space the Görtler vortices are randomly distributed in banded regions on the wall, concentrating at the outflow boundaries of Taylor vortex cel...

In this paper, some ideas for solving Navier-Stokes equations using fractional step techniques in combination with domain decomposition methods are introduced. Apart from its traditional use in a rational distribution of the computational work, the domain decomposition (DD) method can be a powerful tool when dealing with complex geometries, which can have moving parts. The CBS (Characteristic B...

In this study, turbulent compressible gas flow in a rectangular micro-channel is numerically investigated. The gas flow assumed to be in the subsonic regime up to Mach number about 0.7. Five low and high Reynolds number RANS turbulence models are used for modeling the turbulent flow. Two types of mesh are generated depending on the employed turbulence model. The computations are performed for R...

the energy equation for turbulent flow of fiber suspensions was derived in terms of second order correlation tensors. fiber motion of turbulent energy including the correlation between pressure fluctuations and velocity fluctuations was discussed at two points of flow field, at which the correlation tensors were the functions of space coordinates, distance between two points, and time.

In this article, the effects of viscous dissipation and inertial force on the velocity and temperature distributions of the mixed convection laminar flow in a vertical channel partly filled with a saturated porous medium have been studied. In this regard, the Brinkman–Forchheimer extended Darcy model was adopted for the fluid flow in the porous region. In addition, three different viscous dissi...

In this paper we report on (two-component) LDV experiments in a fully developed turbulent pipe flow with a drag-reducing polymer (partially hydrolyzed polyacrylamide) dissolved in water. The Reynolds number based on the mean velocity, the pipe diameter and the local viscosity at the wall is approximately 10000. We have used polymer solutions with three different concentrations which have been c...

Characteristics of enstrophy generation and entrainment velocity at the turbulent non-turbulent interface of a temporally evolving wake are studied using Direct Numerical Simulations (DNS), starting from the time instance when the instabilities develop to a fully turbulent state. Results reveal the dominant role of viscous effects compared to the production of enstrophy at the interface at all ...

[1] The stress and drag at the surface of the ocean are crucial parameters for both short term forecasting and the modeling of long-term global climate trends. However, the partition between viscous, turbulent, and wave stresses, and in particular the effects of airflow separation are not well understood. We present direct measurements of the velocity in the airflow above wind-generated waves. ...

the present article focuses on the evaluation of a first-moment closure model applicable to film cooling flow and heat transfer computations. the present first-moment closure model consists of a higher level of turbulent heat flux modeling in which two additional transport equations for temperature variance kθ and its dissipation rate εθ are considered. it not only employs a time scale that is ...