Time-dependent flows of a Newtonian fluid through periodic arrays of spheres were simulated using the lattice-Boltzmann scheme. By applying a constant body force per unit mass to the fluid, a steady background fluid flow through the array of stationary spheres was first established. Subsequently, a small-amplitude perturbation to the body force, which varied periodically in time, was added and ...

This study concerns numerical simulation, modeling and optimization of aerodynamic stall control using a synthetic jet actuator. Thenumerical simulation was carried out by a large-eddy simulation that employs a RNG-based model as the subgrid-scale model. The flow around a NACA0015 airfoil, including a synthetic jet located at 10 % of the chord, is studied under Reynolds number Re = 12.7 × 106 a...

Bubble column reactors suffer from bubble coalescence resulting in a decreased mass transfer efficiency. In order to increase the mass transfer rate in bubble column reactors, a novel reactor is proposed, the Micro-Structured Bubble Column (MSBC). is novel reactor makes use of a wire-mesh serving the purpose of cuing bubbles into smaller bubbles. is increases the specific bubble surface area...

Air bubbles are used in chemical, biochemical, environmental, and food process for improving the heat and mass transfer. Due to the dominance of non-Newtonian liquids used in various process industries, an understanding of bubble rise in rheologically complex liquids has grown to be important. An experimental study of the bubble rise velocity and drag co-efficient at high Reynolds number in non...

a r t i c l e i n f o An accurate model for the drag coefficient (C D) of a falling sphere is presented in terms of a non-linear rational fractional transform of the series of Goldstein (Proc. Roy. Soc. London A, 123, 225-235, 1929) to Oseen's equation. The coefficients of the six polynomial terms are improved through a direct fit to the experimental data of Roos and Willmarth (AIAA J., 9:285-2...

Bubble column reactors suffer from bubble coalescence resulting in a decreased mass transfer efficiency. In order to increase the mass transfer rate in bubble column reactors, a novel reactor is proposed, the Micro-Structured Bubble Column (MSBC). is novel reactor makes use of a wire-mesh serving the purpose of cuing bubbles into smaller bubbles. is increases the specific bubble surface area...

Bubble column reactors suffer from bubble coalescence resulting in a decreased mass transfer efficiency. In order to increase the mass transfer rate in bubble column reactors, a novel reactor is proposed, the Micro-Structured Bubble Column (MSBC). is novel reactor makes use of a wire-mesh serving the purpose of cuing bubbles into smaller bubbles. is increases the specific bubble surface area...

determining characteristics and behavior of fluid flow and obtaining the aerodynamic coefficients are important and considerable tasks in investigation of flow over the bodies. in this research, leading edge radius effects on the flow behavior over a delta wing with a sweep angle of 50 degree at different reynolds numbers between 0.5×106 and 2.5×106 are investigated numerically. three different...

The adjoint-based sensitivity analyses well explored in hydrodynamic stability studies are extended to calculate the sensitivity of forces acting on an aerofoil with respect to wall transpiration. The magnitude of the sensitivity quantifies the controllability of the force, and the distribution of the sensitivity represents a most effective control when the control magnitude is small enough. Si...