Pressure Energy Diffusion Rates in the Wall-Wake Region of Immobile Solid Sphere in Open Channel Flows-Numerical Simulation and Experimental Study
Tóm tắt
Present study elucidates the near-bed pressure energy diffusion rates in the wall-wake region of flowpast a stationary solid sphere in open channel. Vertical distributions of stream wise velocity and Reynolds shear stresses (RSS) are analysed at seven different locations in order to insight the near-bed pressure energy diffusion rates in the framework of turbulent flow characteristics. ANSYS CFX based model is used for the numerical simulations in association with k–ε numerical model of CFD commercial package whereas, an acoustic Doppler velocimeter (ADV) is used to measure the instantaneous flow velocity for experimental investigations. The results reveal to our understanding of negative pressure energy diffusion rate with increasing turbulence production on the lee side of the solid sphere. The inflections in time-averaged velocity and RSS exhibit up to 2.5 times of the sphere diameter in the wall-wake flow region.
Tài liệu tham khảo
Balachandar, R., Ramachandran, S., and Tachie, M.F., Characteristics of shallow turbulent near wakes at low Reynolds numbers, J. Fluids Eng., 2000, vol. 122, no. 2, pp. 302−308.
Cheong, H. F. and Xue, H., Turbulence model for water flow over two-dimensional bed forms, J. Hydraul. Eng., 1997, vol. 123, no. 5, pp. 402−409.
Dey, S. and Das, R., Gravel-bed hydrodynamics: Double-averaging approach, J. Hydraul. Eng., 2012, vol. 138, no. 8, pp. 707−725.
Dey, S., Sarkar, S., Bose, S.K., Tait, S., and Castro-Orgaz, O., Wall-wake flows downstream of a sphere placed on a plane rough wall, J. Hydraul. Eng., 2011, vol. 137, no. 10, pp. 1173−1189.
Finnigan, J., Turbulence in plant canopies, Annu. Rev. Fluid Mech., 2000, vol. 32, no. 1, pp. 519−571.
Fischer-Antze, T., Stoesser, T., Bates, P., and Olsen, N.R.B., 3D numerical modelling of open-channel flow with submerged vegetation, J. Hydraul. Res., 2001, vol. 39, no. 3, pp. 303−310.
Goring, D.G. and Nikora, V.I., Despiking acoustic Doppler velocimeter data, J. Hydraul. Eng., 2002, vol. 128, no. 1, pp. 117−126.
Iatan, E., Iliescu, M., Bode, F., Nastase, I., Damian, R.M., and Sandu, M., Numerical study for open-channel flow over rows of hemispheres, Energy Procedia, 2016, vol. 85, pp. 260−265.
Malakar, P., Datta, A., and Das, R., Influence of weak bed-load transport on mean flow characteristics over immobile smooth bed surface under dynamic equilibrium flow conditions, Water Resour. Manage., 2020, vol. 34, pp. 4959–4973. https://doi.org/10.1007/s11269-020-02702-5
Mignot, E., Barthélemy, E., and Hurther, D., Turbulent kinetic energy budget in a gravel-bed channel flow, Acta Geophys., 2008, vol. 56, no. 3, pp. 601−613.
Nezu, I. and Nakagawa, H., Turbulence in Open-Channel Flows, Rotterdam, Netherlands: Balkema, 1993.
Nikora, V. and Goring, D., Flow turbulence over fixed and weakly mobile gravel beds, J. Hydraul. Eng., 2000, vol. 126, no. 9, pp. 679−689.
Peric, M., Rüger, M., and Scheuerer, G., Calculation of the Two-Dimensional Turbulent Flow over a Sand Dune Model, Univ. Erlangen, Germany, 1988.
Rameshwaran, P. and Naden, P.S., Three-dimensional numerical simulation of compound channel flows, J. Hydraul. Eng., 2003, vol. 129, no. 8, pp. 645−652.
Raupach, M.R. and Shaw, R.H., Averaging procedures for flow within vegetation canopies, Boundary-Layer Meteorol., 1982, vol. 22, pp. 79−90.
Raupach, M.R., Antonia, R.A., and Rajagopalan, S., Rough-wall turbulent boundary layers, Appl. Mech. Rev., 1991, vol. 44, no. 1, pp. 1−25.
Stoesser, T. and Nikora, V.I., Flow structure over square bars at intermediate submergence: Large Eddy Simulation study of bar spacing effect, Acta Geophysica, 2008, vol. 56, no. 3, pp. 876−893.
Strom, K.B. and Papanicolaou, A.N., ADV measurements around a cluster microform in a shallow mountain stream, J. Hydraul. Eng., 2007, vol. 133, no. 12, pp. 1379−1389.
Yen, C.H., Hui, U.J., We, Y.Y., and Sadikin, A., Numerical study of flow past a solid sphere at high Reynolds number, IOP Conf. Ser.: Mater. Sci. Eng., 2017, 243 012042.