Numerical study on vortex induced vibration of a flexible plate behind square cylinder with various flow velocities

2014 ◽  
Vol 19 (4) ◽  
pp. 488-494 ◽  
Author(s):  
Shi-liang Hu ◽  
Chuan-jing Lu ◽  
You-sheng He
Keyword(s):  
Numerical Study ◽  
Flexible Plate ◽  
Square Cylinder ◽  
Vortex Induced Vibration ◽  
Flow Velocities

Numerical Study on a Single Square Cylinder Subjected to Vortex-Induced Vibration in HTR-PM

2016 ◽  
Author(s):  
Qiankun Xiao ◽  
Li Shi ◽  
Xiaoxin Wang ◽  
Xiaowei Luo ◽  
Xinxin Wu
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Numerical Study ◽  
Flow Direction ◽  
Turbulence Models ◽  
Detached Eddy Simulation ◽  
Square Cylinder ◽  
Vortex Induced Vibration ◽  
Eddy Simulation ◽  
High Reynolds

The heat transfer tube bundles of the steam generator in high temperature reactor pebble bed module (HTR-PM) are subjected to high speed helium flow, which might lead to vortex-induced vibration (VIV). In the present paper, to investigate the vibration of square cylinder under flow effect, vortex shedding phenomena of a stationary square cylinder at a high Reynolds number equal to 6.8 × 104 is simulated by detached eddy simulation (DES) turbulence models. A comparatively close agreement with previous experimental results is achieved. Combining computational fluid dynamics (CFD) and computational structural dynamics (CSD) methods, a fluid-structure-interaction (FSI) model for VIV of the square cylinder is then established, and vibration response perpendicular to flow direction were investigated. Moreover, the safe range of the natural frequency of the square cylinder to avoid synchronized vibration with VIV is analyzed. The results of this paper can provide an important guidance to the design of the heat transfer tubes and their supports in HTR-PM.

Numerical Prediction of Turbulent Wakes Behind a Square Cylinder

1998 ◽  
Vol 14 (1) ◽  
pp. 23-29
Author(s):  
Robert R. Hwang ◽  
Sheng-Yuh Jaw
Keyword(s):  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Wall Region ◽  
Square Cylinder ◽  
Mean Velocity ◽  
Navier Stokes Equations ◽  
Turbulent Vortex Shedding ◽  
Model Equations ◽  
Good Agreement

ABSTRACTThis paper presents a numerical study on turbulent vortex shedding flows past a square cylinder. The 2D unsteady periodic shedding motion was resolved in the calculation and the superimposed turbulent fluctuations were simulated with a second-order Reynolds-stress closure model. The calculations were carried out by solving numerically the fully elliptic ensemble-averaged Navier-Stokes equations coupled with the turbulence model equations together with the two-layer approach in the treatment of the near-wall region. The performance of the computations was evaluated by comparing the numerical results with data from available experiments. Results indicate that the present study gives good agreement in the shedding frequency and mean drag as well as in some phase profiles of the mean velocity.

scholarly journals Piezoelectric Wind Energy Harvesting from Self-Excited Vibration of Square Cylinder

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Junlei Wang ◽  
Sheng Wen ◽  
Xingqiang Zhao ◽  
Min Zhang ◽  
Jingyu Ran
Keyword(s):  
Wind Energy ◽  
Aerodynamic Force ◽  
Load Resistance ◽  
Open Circuit ◽  
Transverse Displacement ◽  
Square Cylinder ◽  
Force Output ◽  
Vortex Induced Vibration ◽  
Wind Speeds ◽  
Excited Vibration

Self-excited vibration of a square cylinder has been considered as an effective way in harvesting piezoelectric wind energy. In present work, both of the vortex-induced vibration and unstable galloping phenomenon process are investigated in a reduced velocity (Ur=U/ωn·D) range of4≤Ur≤20with load resistance ranging in100 Ω≤R≤1 MΩ. The vortex-induced vibration covers presynchronization, synchronization, and postsynchronization branches. An aeroelectromechanical model is given to describe the coupling of the dynamic equation of the fluid-structure interaction and the equation of Gauss law. The effects of load resistance are investigated in both the open-circuit and close-circuit system by a linear analysis, which covers the parameters of the transverse displacement, aerodynamic force, output voltage, and harvested power utilized to measure the efficiency of the system. The highest level of the transverse displacement and the maximum value of harvested power of synchronization branch during the vortex-induced vibration and galloping are obtained. The results show that the large-amplitude galloping at high wind speeds can generate energy. Additionally, energy can be harvested by utilization of the lock-in phenomenon of vortex-induced vibration under low wind speed.

scholarly journals Temperature and Velocity Effects on Mass and Momentum Transport in Spacer-Filled Channels for Reverse Electrodialysis: A Numerical Study

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2028 ◽  
Author(s):  
Zohreh Jalili ◽  
Jon Pharoah ◽  
Odne Stokke Burheim ◽  
Kristian Einarsrud
Keyword(s):  
Mass Transfer ◽  
Pressure Drop ◽  
Concentration Polarization ◽  
Numerical Study ◽  
Membrane Surface ◽  
Lower Pressure ◽  
Low Flow ◽  
Fluid Temperature ◽  
Reverse Electrodialysis ◽  
Flow Velocities

Concentration polarization is one of the main challenges of membrane-based processes such as power generation by reverse electrodialysis. Spacers in the compartments can enhance mass transfer by reducing concentration polarization. Active spacers increase the available membrane surface area, thus avoiding the shadow effect introduced by inactive spacers. Optimizing the spacer-filled channels is crucial for improving mass transfer while maintaining reasonable pressure losses. The main objective of this work was to develop a numerical model based upon the Navier–Stokes and Nernst–Planck equations in OpenFOAM, for detailed investigation of mass transfer efficiency and pressure drop. The model is utilized in different spacer-filled geometries for varying Reynolds numbers, spacer conductivity and fluid temperature. Triangular corrugations are found to be the optimum geometry, particularly at low flow velocities. Cylindrical corrugations are better at high flow velocities due to lower pressure drop. Enhanced mass transfer and lower pressure drop by elevating temperature is demonstrated.

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