We develop an analytic approach to two-dimensional flow separation control by feedback. With two wall-based actuators enclosing an array of distributed wall-shear sensors, we control the wall-shear evolution equation through its boundary values at the actuators. Using this approach, we induce separation at prescribed locations in steady and unsteady channel flows, and reduce the recirculation l...

The heart is a heterogeneous tissue composed of several cell types tailored for specialized functions. We found that intracellular channels also exhibit regional specialization. In cardiac and skeletal muscle these channels are called the calcium-release channel and are identified by activation with either calcium or caffeine and inhibition by the hexavalent cation ruthenium red. The calcium-re...

The migratory abilities of motile human spermatozoa in vivo are essential for natural fertility, but it remains a mystery what properties distinguish the tens of cells which find an egg from the millions of cells ejaculated. To reach the site of fertilization, sperm must traverse narrow and convoluted channels, filled with viscous fluids. To elucidate individual and group behaviors that may occ...

a r t i c l e i n f o a b s t r a c t Heat-transfer enhancement in a uniformly heated slot mini-channel due to vortices shed from an adiabatic circular cylinder is numerically investigated. The effects of gap spacing between the cylinder and bottom wall on wall heat transfer and pressure drop are systemically studied. Numerical simulations are performed at Re = 100, 0.1 Pr 10 and a blockage rat...

We study the effect of droplet coalescence on turbulent wall-bounded flows by means direct numerical simulations. In particular, volume-of-fluid and front-tracking methods are used to simulate channel containing coalescing non-coalescing droplets, respectively. find that droplets have a negligible drag, whereas ones steadily increase drag as volume fraction dispersed phase increases: indeed, at...

In this work transient mixed convection in a porous medium in a horizontal channel with a open cavity below is studied numerically. The cavity presents a heated wall at uniform heat flux and the other walls of the cavity and the channel are assumed adiabatic. Air flows through the horizontal channel. The heated wall of the cavity experiences a uniform heat flux in such a way that the forced flo...

We investigate statistics of large-scale structures from large-eddy simulation (LES) of turbulent channel flow at friction Reynolds numbers Reτ =2K and 200K (where K denotes 1000). In order to capture the behaviour of large-scale structures properly, the channel length is chosen to be 96 times the channel half-height. In agreement with experiments, these large-scale structures are found to give...

Numerical simulation is performed to investigate the laminar force convection of Al2O3/water nanofluid in a flow channel with discrete heat sources. The heat sources are placed on the bottom wall of channel which produce much thermal energy that must be evacuated from the system. The remaining surfaces of channel are kept adiabatic to exchange energy between nanofluid and heat sources. In the p...

A model of a two-stage thruster with anode layer is developed based on a two-dimensional hydrodynamic approach. Each stage is considered separately, while the solution of the first stage provides the boundary conditions for the second stage.Current-voltage characteristic of the discharge in thefirst stage is calculated and is found to be in agreement with experiment. In the acceleration channel...