The effect of Reynolds number on near-wall reverse flow in a turbulent duct flow

The influence of the Reynolds number on the statistics of a near-wall reverse flow phenomenon, taking place in a turbulent duct flow, is studied. An increase in the NWRF probability is found in both the core and corner regions of the duct walls for higher Reynolds number. The mechanism of the NWRF formation, described recently by Zaripov et al. [1, 2], is validated for higher Reynolds number flows.

An energy, momentum and angular momentum conserving scheme for a regularization model of incompressible flow

We introduce a new regularization model for incompressible fluid flow, which is a regularization of the EMAC (energy, momentum, and angular momentum conserving) formulation of the Navier-Stokes equations (NSE) that we call EMAC-Reg. The EMAC formulation has proved to be a useful formulation because it conserves energy, momentum and angular momentum even when the divergence constraint is only weakly enforced. However, it is still a NSE formulation and so cannot resolve higher Reynolds number flows without very fine meshes. By carefully introducing regularization into the EMAC formulation, we create a model more suitable for coarser mesh computations but that still conserves the same quantities as EMAC, i.e., energy, momentum, and angular momentum. We show that EMAC-Reg, when semi-discretized with a finite element spatial discretization is well-posed and optimally accurate. Numerical results are provided that show EMAC-Reg is a robust coarse mesh model.

An Experimental Investigation of Flow Phenomena in a Multi-Stage Micro Tesla Valve

The Tesla-diode valve, with no moving parts, allows restricted flow in one direction. It has many potential applications in different industrial situations. Despite the application of the valve and the importance of the effect of flow phenomena on the Tesla valve's performance, very few studies have experimentally investigated the motion of flow within the Tesla valve. This study aims to contribute to this growing area of research on the performance of Tesla valves by demonstrating the flow phenomena and the flow conditions needed to be used in numerical studies. In this work, the effect of direction of the flow and Reynolds number on the flow phenomena generated in a Tesla-diode valve is studied. Particle shadowgraph velocimetry (PSV) is utilized to investigate and visualize the velocity field. The results of this study confirm some of the phenomena that has been observed using numerical simulations. It also highlights the flow phenomena leading to an increase in the diodicity by an increase in the number of Tesla loops in the valve. An important observation often ignored in numerical simulation is the presence of unsteady behavior and vortex shedding for higher Reynolds number flows.

Computational fluid dynamic simulation of airfoils in unsteady low Reynolds number flows

Computational fluid dynamic simulation of airfoils in unsteady low Reynolds number flows

Computational fluid dynamic simulation of airfoils in unsteady low Reynolds number flows

Computational fluid dynamic simulation of airfoils in unsteady low Reynolds number flows