The advent of microelectromechanical systems (MEMS) sensors has enabled real-time wall shear stress (WSS) measurements with high spatial and temporal resolution in a 3-D bifurcation model. To optimize intravascular shear stress assessment, we evaluated the feasibility of catheter/coaxial wire-based MEMS sensors in the abdominal aorta of the New Zealand white (NZW) rabbits. Theoretical and compu...

[1] We examine wave-current interactions in littoral current shear instabilities above a single-barred beach using a fully coupled wave and barotropic current model based on the multiscale asymptotic theory derived by McWilliams et al. (2004). This Eulerian waveaveraged model captures wave effects on currents (WEC) in a manner that leads to simple interpretations. The dynamically conservative W...

the purpose of this paper is to studying nonlinear k-ε turbulence models and its advantages in internal combustion engines, since the standard k-ε model is incapable of representing the anisotropy of turbulence intensities and fails to express the reynolds stresses adequately in rotating flows. therefore, this model is not only incapable of expressing the anisotropy of turbulence in an engine c...

This study numerically investigates the vortex-induced vibration (VIV) of an elastically mounted rigid cylinder by using Reynolds-averaged Navier-Stokes (RANS) equations with computational fluid dynamic (CFD) tools. CFD analysis is performed for a fixed-cylinder case with Reynolds number (Re) = 104 and for a cylinder that is free to oscillate in the transverse direction and possesses a low mass...

Turbulence equilibrium state is analyzed for the modeled Reynolds-stress transport equation, assuming most general formulation of pressure–strain correlation. In a two-dimensional mean flow at high-Reynolds number, an algebraic equation system obtained, providing anisotropies as functions model coefficients. Conversely, equations provide calibration conditions coefficients to predict specified ...

The two-dimensional low-speed structure of a turbulent boundary layer has been clearly visualized by a combination of a shear stress sensor using micro electro mechanical systems and the discrete wavelet transform. The application of two-dimensional discrete wavelet transforms to the visualization of wall shear stress data obtained using the micro shear stress imaging chip is described. The exp...

The physical mechanisms by which the Reynolds shear stress is produced from dynamically evolving vortical structures in the wall region of a direct numerical simulation of turbulent channel flow are explored. The complete set of quasistreamwise vortices are systematically located and tracked through the flow by the locus of the points of intersection of their centres of rotation with the ( y , ...

The wall-normal gradient of Reynolds shear stress, denoted ∂T+/∂y+, may be thought of as a momentum source or sink term (depending on its sign). This quantity represents a critical driver of the dynamics of wall-turbulence that give rise to the mean velocity distribution. While there have been a number of studies concerning the statistics of ∂T+/∂y+, there remains much to discover regarding the...

Manoeuvring underwater vehicles experience complex three dimensional flow. Features include stagnation and boundary layer separation along a convex surface. The resulting free vortex sheet rolls up to form a pair of streamwise body vortices. The track and strength of the body vortex pair results in a nonlinear increase in lift with as body incidence increases. Consequently, accurate capture of ...

In this paper, an investigation into the effect of explicit non-linear turbulence modelling on anisotropic flows is presented. Such are typified in corner separations turbomachinery. The commonly used Reynolds-Averaged Navier-Stokes (RANS) closures, which Reynolds stress tensor modelled by Boussinesq (linear) constitutive relation with mean strain-rate tensor, often struggle to predict separati...