a lattice boltzmann method is applied to demonstrate the comparison results of simulating natural convection in an open end cavity using different hydrodynamic and thermal boundary conditions. the prandtl number in the present simulation is 0.71, rayleigh numbers are 104,105 and 106 and viscosities are selected 0.02 and 0.05. on-grid bounce-back method with first-order accuracy and non-slip met...

Field studies show that the internal screens in a gross pollutant trap (GPT) are often clogged with organic matter, due to infrequent cleaning. The hydrodynamic performance of a GPT with fully blocked screens was comprehensively investigated under a typical range of onsite operating conditions. Using an acoustic Doppler velocimeter (ADV), velocity profiles across three critical sections of the ...

Myliobatidae is a family of large pelagic rays including the manta ray, Manta birostris. They are extremely efficient swimmers, can cruise at high speeds and can perform turn-on-a-dime maneuvering, making these fishes excellent inspiration for an autonomous underwater vehicle. Manta rays have been studied from a biological perspective; however the hydrodynamic performance of their large-amplitu...

The performance of a diffuser in a pump stage depends on its configuration and placement within the stage. The influence of vane shape on the hydrodynamic performance of a diffuser has been studied. The goal of this effort has been to improve the performance of a pump stage by optimizing the shape of the diffuser vanes. The shape of the vanes was defined using Bezier curves and circular arcs. S...

Some specialized aquatic snakes such as Natrix tessellata strike at fish by rapidly accelerating their head towards the prey with their mouth opened widely. This strategy is believed to be suboptimal as relatively high drag forces act on the open jaws and, therefore, probably limit strike speed. Moreover, the bow wave in front of the snake's jaws could push prey away from the mouth, thus potent...

Maneuverability is one of the most important and least understood aspects of animal locomotion. The hydrofoil-like flippers of cetaceans are thought to function as control surfaces that effect maneuvers, but quantitative tests of this hypothesis have been lacking. Here, we constructed a simple hydrodynamic model to predict the longitudinal-axis roll performance of fin whales, and we tested its ...

A computational study of fish fin hydrodynamics is being conducted concurrently with experimental analysis. The presence of a complex shaped moving boundary makes this a difficult proposition for computational fluid dynamics and here we use a Cartesian grid based immersed boundary solver designed to handle such flows in all their complexity. High resolution, high speed video of fish fin movemen...

Surface texturing is an important approach for controlling the tribological behavior of friction pairs used in mechanical and biological engineering. In this study, by utilizing the method of three-dimensional computational fluid dynamics (CFD) simulation, the lubrication model of a friction pair with micro-dimple array was established based on the Navier-Stokes equations. The typical pressure ...

an attempt is made for the first time to solve the quadratic and cubic model of magneto hydrodynamic poiseuille flow of phan-thein-tanner (ptt). series solution of magneto hydrodynamic (mhd) flow is developed by using homotopy perturbation method (hpm). results are presented graphically and the effects of non-dimensional parameters on the flow field are analyzed. the results obtained reveals ma...