The problem of turbulent flow in a rough pipe of arbitrary shape is considered. The classical Izakson-Millikan argument for a logarithmic velocity profile is presented, and matched asymptotic expansions are introduced. Scaled, dimensionless equations are produced and simplified. A simple mixing length turbulence model is presented, which closes the problem. To calibrate the model, the mechanica...

In this study, the effects of thermal and hydraulic characteristics of wavy fin and tube heat exchanger are investigated. Simulation has been carried out by a commercial computational fluid dynamics code, ANSYS CFX12.0. The main objective of this study is to investigate the flow characteristics in turbulent flow. Results are predicted for the turbulent flow regime (2100≤Re≤7000) and compared wi...

this study is concerned with the prediction of particles’ velocity in a dilute turbulent gas-solidboundary layer flow using a fully eulerian two-fluid model. the closures required for equationsdescribing the particulate phase are derived from the kinetic theory of granular flows. gas phaseturbulence is modeled by one-equation model and solid phase turbulence by mlh theory. resultsof one-way and...

The study is focused on the mathematical modelling of leakage flow in very narrow channels. The problem is solved as a two-dimensional non-stationary turbulent compressible Newtonian fluid flow with ideal gas properties. The turbulent flow is assumed to be statistically steady and the mathematical model is described by the non-linear conservative system of the compressible Favre-averaged Navier...

Plane Couette flow presents a regular oblique turbulent-laminar pattern over a wide range of Reynolds numbers R between the globally stable base flow profile at low R < Rg and a uniformly turbulent regime at sufficiently large R > Rt. The numerical simulations that we have performed on a pattern displaying a wavelength modulation show a relaxation of that modulation in agreement with what one w...

Related Articles Lagrangian evolution of the invariants of the velocity gradient tensor in a turbulent boundary layer Phys. Fluids 24, 105104 (2012) Effects of moderate Reynolds numbers on subsonic round jets with highly disturbed nozzle-exit boundary layers Phys. Fluids 24, 105107 (2012) Particle transport in a turbulent boundary layer: Non-local closures for particle dispersion tensors accoun...

Data on turbulent mixing and other turbulent-flow phenomena suggest that a (mixing) transition, originally documented to occur in shear layers, also occurs in jets, as well as in other flows and may be regarded as a universal phenomenon of turbulence. The resulting fully-developed turbulent flow requires an outer-scale Reynolds number of Re = U δ/ν > ∼ 1 − 2 × 10 4 , or a Taylor Reynolds number...

Related Articles Lagrangian evolution of the invariants of the velocity gradient tensor in a turbulent boundary layer Phys. Fluids 24, 105104 (2012) Effects of moderate Reynolds numbers on subsonic round jets with highly disturbed nozzle-exit boundary layers Phys. Fluids 24, 105107 (2012) Particle transport in a turbulent boundary layer: Non-local closures for particle dispersion tensors accoun...

A method for the simultaneous measurement of velocity and passive scalar concentration fields by means of particle image velocimetry (PIV) and planar laser induced florescence (PLIF) techniques is described here. An application of the combined PIV-PLIF system is demonstrated by performing simultaneous velocity and concentration measurements in the near field of a turbulent jet mixing flow. The ...

Related Articles Lagrangian evolution of the invariants of the velocity gradient tensor in a turbulent boundary layer Phys. Fluids 24, 105104 (2012) Effects of moderate Reynolds numbers on subsonic round jets with highly disturbed nozzle-exit boundary layers Phys. Fluids 24, 105107 (2012) Particle transport in a turbulent boundary layer: Non-local closures for particle dispersion tensors accoun...