Effect of Slit Inclusions in Drag Reduction of Flow over Cylinders

Abstract:

The flow over bluff bodies is separated compared to the flow over streamlined bodies. The investigation of the fluid flow over a cylinder with a streamwise slit has received little attention in the past, however there is some experimental evidence that show for turbulent regime it reduces the drag coefficient. This work helps in understanding the fluid flow over such cylinders in the laminar regime. As the width of the slit increases the drag coefficient keeps on reducing resulting in a narrower wake as compared to what is expected for flow over a cylinder. In this work we have used two different approaches in modelling a 2D flow for Re=10 to compare the results for CFD using finite volume method (ANSYS FLUENT^TM) and Lattice Boltzmann methods. In all cases cylinders of circular cross section have been considered while slit width changing from 10% to 40% of the cylinder diameter. . It will be shown that drag coefficient decreases as the slit ratio increases. The effect of slit size on drag reduction is studied and discussed in detail in the paper. We have also made comparison of the results obtained from Lattice Boltzmann and finite volume methods.

• Periodical: Applied Mechanics and Materials (Volume 846)
• Pages: 18-22
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.846.18
• Online since: July 2016
• Authors: Rohit Bhattacharya, Abouzar Moshfegh, Ahmad Jabbarzadeh*
• Keywords: Computational Fluid Dynamics (CFD), Drag Reduction, Flow over Slit Cylinder, Lattice-Boltzmann

References

[1] Liaw, K. (2005). Simulation of flow around bluff bodies and bridge deck sections using CFD (Doctoral dissertation, University of Nottingham).

[2] Olsen, J. F., & Rajagopalan, S. (2000). Vortex shedding behind modified circular cylinders. Journal of Wind Engineering and Industrial Aerodynamics, 86(1), 55-63.

DOI: 10.1016/s0167-6105(00)00003-9

[3] Dixon, A. G., Nijemeisland, M., & Stitt, E. H. (2006). Packed tubular reactor modeling and catalyst design using computational fluid dynamics. Advances in Chemical Engineering, 31, 307-389.

DOI: 10.1016/s0065-2377(06)31005-8

[4] Latt, J. (2008). Choice of units in lattice Boltzmann simulations. Freely available online at http: /lbmethod. org/_media/howtos: lbunits. pdf.

[5] Askes, H., Kuhl, E., & Steinmann, P. (2004). An ALE formulation based on spatial and material settings of continuum mechanics. Part 2: Classification and applications. Computer methods in applied mechanics and engineering, 193(39), 4223-4245.

DOI: 10.1016/j.cma.2003.09.031

[6] Caiazzo, A., & Junk, M. (2008). Boundary forces in lattice Boltzmann: Analysis of momentum exchange algorithm. Computers & Mathematics with Applications, 55(7), 1415-1423.

DOI: 10.1016/j.camwa.2007.08.004

[7] Dinesh, J. (2009). Modelling and Simulation of a Single Particle in Laminar Flow Regime of a Newtonian Liquid. In COMSOL Conference. Bangalore, India.

[8] Tuann, S. Y., & Olson, M. D. (1978). Numerical studies of the flow around a circular cylinder by a finite element method. Computers & Fluids, 6(4), 219-240.

DOI: 10.1016/0045-7930(78)90015-4

[9] Beaudan, P., & Moin, P. (1994). Numerical experiments on the flow past a circular cylinder at sub-critical Reynolds number (No. TF-62). STANFORD UNIV CA THERMOSCIENCES DIV.

[10] Biswas, R., & Strawn, R. C. (1998). Tetrahedral and hexahedral mesh adaptation for CFD problems. Applied Numerical Mathematics, 26(1), 135-151.

DOI: 10.1016/s0168-9274(97)00092-5

[11] Bloor, M. S. (1964). The transition to turbulence in the wake of a circular cylinder. Journal of Fluid Mechanics, 19(02), 290-304.

DOI: 10.1017/s0022112064000726

[12] Abhijeet, T (2011). Introduction to the Lattice Boltzmann Method. 10th Indo-German Winter Academy 2011, IIT Kharagpur, India.