Numerical Investigation of Different Flow Regimes for Square Cylinders in Staggered Configuration
- 35 Downloads
The present numerical investigation deals with the flow across two square cylinders placed in staggered alignment at fixed Reynolds number (Re) of 160 and varying gap spacings (g*) from 0 to 6. Numerical computations are conducted by employing the two-dimensional single-relaxation-time lattice Boltzmann method (SRT-LBM). The complex phenomena of vortex shedding are explored for different g* and outcomes are presented as vorticity snapshots, time-history analysis of drag and lift coefficients (CD and CL) and power spectra analysis of CL. Five flow patterns are observed which are named as: single bluff body flow, quasi periodic flow, chaotic flow, in-phase/anti-phase modulated flow and synchronized flow. The fluid forces are irregular for all flow patterns except for synchronized flow where lift is periodic due to synchronization of flow. It is observed that presence of an upstream cylinder in the near vicinity of downstream cylinder increases the drag at small gap spacing and vice versa.
Keywordsflow pattern gap spacing lattice boltzmann method numerical analysis square cylinders staggered arrangement
Unable to display preview. Download preview PDF.
- Fredsoe, J. and Sumer, M. B. (1997). “Hydrodynamics around cylindrical structures.” World scientific Publishing, Vol. 26, DOI: 10.1142/6248.Google Scholar
- Gera, B. Sharma, P. K., and Singh, R. K. (2010). “CFD analysis of 2D unsteady flow around a square cylinder.” International Journal of Applied Engineering Research, Vol. 3. No. 1, pp. 602–612, DOI: 10.1051/itmconf/20181602003.Google Scholar
- Guo, Z. and Chang, S. (2013). “Lattice Boltzmann method and its applications in engineering.” World Scientific, Vol. 3, DOI: 10.1142/8806.Google Scholar
- Islam, S. U., Abbasi, W. S., and Rahman, H. (2014). “Force statistics and Wake Structure Mechanism of flow around a square cylinder at low Reynolds numbers.” International Journal of Mechanical, Aerospace, Industrial and Mechatronics Engineering, Vol. 8, No. 8, pp. 1417–1423, DOI: 10.5281/zenodo.1094333.Google Scholar
- Islam, S. U., Abbasi, W. S., Rahman, H., and Naheed, R. (2016). “Numerical investigation of wake modes for flow past three tandem cylinders using the multi-relaxation-time lattice Boltzmann method for different gap spacings.” Journal of the Brazilian Society of Mechanical Sciences and Engineering, Vol. 38, No. 3, pp. 799–812, DOI: 10.1007/s40430-014-0282-4.CrossRefGoogle Scholar
- Islam, S. U., Nazeer, G., Islam, Z. U., Ying, Z. C., and Manzoor, R. (2017). “Transitions in the flow patterns and aerodynamic characteristics of the flow around staggered rows of cylinders.” PLOS One, Vol. 12, No. 10, p. e0184169, DOI: 10.1371/journal.pone.0184169.Google Scholar
- Islam, S. U., Rahman, H., Ying, Z. C., and Saha, S. A. (2016). “Comparison of wake structures and force measurements behind three side by side cylinders.” Journal of the Brazilian Society of Mechanical Sciences and Engineering, Vol. 38, No. 3, pp. 843–858, DOI: 10.1007/s40430-014-0297-x.CrossRefGoogle Scholar
- Sohankar, A., Norberg, C., and Davidson, L. (1998). “Low-Reynoldsnumber flow around a square cylinder at incidence: Study of blockage, onset of vortex shedding and outlet boundary condition.” International Journal for Numerical Methods in Fluids, Vol. 26, No. 1, pp. 39–56, DOI: 10.1002/(SICI)1097-0363(19980115)26:1< 39::AID-FLD623>3.0.CO;2-P.CrossRefzbMATHGoogle Scholar
- Sukop, M. C. and Thorne, D. T. Jr. (2006). Lattice boltzmann modeling: An introduction for geoscientists and engineers, Springer, Berlin, Heidelberg, Germany, DOI: 10.1007/978-3-540-27982-2.Google Scholar