Numerical Simulation of CUBRC Wake Flow Experiments Using a Hybrid LES/RANS Approach

2013 ◽  
Author(s):  
Giovanni Salazar ◽  
Jack Edwards
Keyword(s):  
Numerical Simulation ◽  
Wake Flow ◽  
Flow Experiments

scholarly journals Numerical simulation on hydrodynamic performance of parallel twin vertical axis tidal current turbines

2019 ◽  
Vol 1 (2) ◽  
pp. Manuscript
Author(s):  
Sun Ke ◽  
Zhou Xuehan ◽  
Li Yan ◽  
Zhang Liang
Keyword(s):  
Numerical Simulation ◽  
Open Source Software ◽  
Average Power ◽  
Vertical Axis ◽  
Lateral Force ◽  
Wake Flow ◽  
Hydrodynamic Performance ◽  
Lateral Distance ◽  
Profile Distribution ◽  
Hydro Turbines

The single and parallel twin vertical axis hydro turbines were numerical simulated by open source software-OpenFOAM, emphatically studied on the interference effect such as torque and load of turbine as well as hydrodynamic performance influenced by the distance and rotation forms between twin turbines and analysed the wake flow field to show the velocity profile distribution. Results show that the average power of parallel twin turbines is always higher than the power of a single turbine, the closer the lateral distance between turbines, the higher the power. At the same time, opposite inward rotation is the best arrangement form for twin turbines to get more power and counteract lateral force.

scholarly journals Direct Numerical Simulation of Water Droplets in Turbulent Flow

Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 158
Author(s):  
Weibo Ren ◽  
Jonathan Reutzsch ◽  
Bernhard Weigand
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Flow ◽  
Surface Deformation ◽  
Terminal Velocity ◽  
Wake Flow ◽  
Recirculation Region ◽  
Drop Surface ◽  
Simulation Code ◽  
Axis Ratio

Details on the fall speeds of raindrops are essential in both applications and natural events, such as rain-rate retrieval and soil erosion. Here, we examine the influence of turbulence on the terminal velocity of two water drops of different sizes. For the first time, computations of droplets in turbulent surroundings are conducted with a direct numerical simulation code based on a volume of fluid method. Both the drop surface deformation and internal circulation are captured. The turbulence intensity at the inflow area, as well as the turbulence length scale are varied. In turbulent flow, we find a decline in the terminal velocities for both drops. Based on the study of the wake flow characteristics and drop surface deformation, the decrease in the terminal velocity is found to be directly linked to a shortening of the wake recirculation region resulting from an earlier and more drastic increase in the turbulence kinetic energy in the shear layer. The turbulent surroundings trigger substantial rises in the drop axis ratio amplitude and a slight increase in the drop oscillation frequency, but barely influence the time-averaged drop axis length.

Numerical Simulation of Non-Equal Diameter Cylinder

2012 ◽  
Vol 249-250 ◽  
pp. 527-532
Author(s):  
Guang Jun Yang ◽  
Jing Sun
Keyword(s):  
Numerical Simulation ◽  
Vortex Shedding ◽  
Wake Flow ◽  
Subcritical State ◽  
Equivalent Diameter ◽  
Freestream Velocity ◽  
Transition Area ◽  
Vortex Shedding Frequency ◽  
Shedding Frequency ◽  
Different Diameters

Numerical simulation has been carried out on the wake flow structure of some simplified antenna model which is shaped as a non-equal diameter slender cylinder. The unsteady flow parameter-Strouhal number is confirmed to be a constant approximately in the subcritical state. The results show that at levels of different diameters, when the length-diameter ratio is large enough, each level can still maintain stable periodical vortex shedding phenomenon, the vortex shedding frequency of each level, the flow velocity and the equivalent diameter still meet the Strouhal relationship. The effect of connect transition area on vortex shedding stabilize region are close to the freestream velocity.

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