Turbulent Structures in Gap Flow
DOI:
https://doi.org/10.37934/cfdl.14.2.2434Keywords:
Navier-Stokes, fluid structures, open channel, gap flow, computational fluid dynamicsAbstract
A computational study was carried out to investigate the effect of the gap between the body and the bed on the wake characteristics in shallow flows. A sharp-edged bluff body with two different clearances from the bed is employed in this investigation. The transient three-dimensional governing Navier-Stokes equations are numerically solved using a finite volume formulation with improved delayed detached-eddy simulation as a turbulence model. The volume of fluid approach is used in the current study as a free-surface modelling technique for locating and tracking the free surface. It is found that the existence and size of the gap influence the wake size and the location where the free surface is restored to its original and flat shape. This study also reveals that the fluid structures lose their symmetry about the center of the wake as the gap size increases.
References
Shinneeb, A-M., and R. Balachandar. "Effect of gap flow on the shallow wake of a sharp-edged bluff body–turbulence parameters." Journal of Turbulence 17, no. 1 (2016): 122-155. https://doi.org/10.1016/j.jasrep.2016.05.067https://doi.org/10.1080/14685248.2015.1088156
Shinneeb, A-M., R. Balachandar, and K. Zouhri. "Effect of gap flow on the shallow wake of a sharp-edged bluff body—Coherent structures." Physics of Fluids 30, no. 6 (2018): 065107. https://doi.org/10.1063/1.5022252
Martinuzzi, R. J., and M. AbuOmar. "Study of the flow around surface-mounted pyramids." Experiments in fluids 34, no. 3 (2003): 379-389. https://doi.org/10.1007/s00348-003-0594-0
Bosch, G., M. Kappler, and W. Rodi. "Experiments on the flow past a square cylinder placed near a wall." Experimental thermal and fluid science 13, no. 3 (1996): 292-305. https://doi.org/10.1016/S0894-1777(96)00087-8
Essel, Ebenezer E., Mark F. Tachie, and Ram Balachandar. "Time-resolved wake dynamics of finite wall-mounted circular cylinders submerged in a turbulent boundary layer." Journal of Fluid Mechanics 917 (2021). https://doi.org/10.1017/jfm.2021.265
Nasif, G., R. Balachandar, and R. M. Barron. "Mean characteristics of fluid structures in shallow-wake flows." International Journal of Multiphase Flow 82 (2016): 74-85. https://doi.org/10.1016/j.ijmultiphaseflow.2016.03.001
Nasif, G., R. Balachandar, and R. M. Barron. "Influence of bed proximity on the three-dimensional characteristics of the wake of a sharp-edged bluff body." Physics of Fluids 31, no. 2 (2019): 025116. https://doi.org/10.1063/1.5085666
Yazid, MNA Mohd. "Large Eddy Simulations of Pollutant Dispersion in a Street Canyon." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 8, no. 1 (2015): 11-19.
Mustaffa, Siti Hajar Adni, Fatimah Al Zahrah Mohd Saat, and Ernie Mattokit. "Turbulent Vortex Shedding across Internal Structure in Thermoacoustic Oscillatory Flow." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 46, no. 1 (2018): 175-184.
Shinneeb, A-M., G. Nasif, and R. Balachandar. "Effect of the aspect ratio on the velocity field of a straight open-channel flow." Physics of Fluids 33, no. 8 (2021): 085110. https://doi.org/10.1063/5.0057343
Nichols, B. D., C. W. Hirt, and R. S. Hotchkiss. "Volume of fluid (VOF) method for the dynamics of free boundaries." J. Comput. Phys 39 (1981): 201-225. https://doi.org/10.1016/0021-9991(81)90145-5
Menter, Florian R. "Two-equation eddy-viscosity turbulence models for engineering applications." AIAA journal 32, no. 8 (1994): 1598-1605. https://doi.org/10.2514/3.12149
Menter, F. R., and M. Kuntz. "Adaptation of eddy-viscosity turbulence models to unsteady separated flow behind vehicles." In The aerodynamics of heavy vehicles: trucks, buses, and trains, pp. 339-352. Springer, Berlin, Heidelberg, 2004. https://doi.org/10.1007/978-3-540-44419-0_30
Spalart, Philippe R., and Craig Streett. Young-person's guide to detached-eddy simulation grids. No. NAS 1.26: 211032. 2001.
Spalart, Philippe R. "Detached-eddy simulation." Annual review of fluid mechanics 41 (2009): 181-202. https://doi.org/10.1146/annurev.fluid.010908.165130
Nasif, G., R. Balachandar, and R. M. Barron. "Supercritical flow characteristics in smooth open channels with different aspect ratios." Physics of Fluids 32, no. 10 (2020): 105102. https://doi.org/10.1063/5.0021609
Nasif, Ghassan Gus. "CFD Simulation of Oil Jets with Application to Piston Cooling." (2014).
Nasif, G., R. M. Barron, and R. Balachandar. "Numerical simulation of piston cooling with oil jet impingement." Journal of Heat Transfer 138, no. 12 (2016). https://doi.org/10.1115/1.4034162
Singha, A. "Shallow Wake in Open Channel Flow–Look into the Vertical Variability (Ph. D. dissertation)." Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Canada (2009).
Heidari, Mehdi, Ram Balachandar, Vesselina Roussinova, and Ronald M. Barron. "Characteristics of flow past a slender, emergent cylinder in shallow open channels." Physics of Fluids 29, no. 6 (2017): 065111. https://doi.org/10.1063/1.4986563
Akilli, H. Ü. S. E. Y. İ. N., and D. O. N. A. L. D. Rockwell. "Vortex formation from a cylinder in shallow water." Physics of Fluids 14, no. 9 (2002): 2957-2967. https://doi.org/10.1063/1.1483307
Nasif, G., R. Balachandar, and R. M. Barron. "Characteristics of flow structures in the wake of a bed-mounted bluff body in shallow open channels." Journal of Fluids Engineering 137, no. 10 (2015). https://doi.org/10.1115/1.4030537
Maheo, P. "Free Surface Turbulent Shear Flow (Ph. D. dissertation)." California Institute of Technology, CA, USA (1999).
