Abstract
Objectives: To examine the effect of unequal gap spacing for flow past over three rectangular rods a fixed Re (Reynolds number) and Aspect Ratio (AR). Methodology: A two dimensional (2-D) numerical study of flow over three rectangular rods is conducted by using Single Relaxation Time Lattice Boltzmann Method (SRT-LBM). The gap spacing (g) between the rods is varied from 0.5 to 7 with fixed Reynolds number i.e., Re = 150 (Re = .U∞d/ υ., where U∞ is uniform velocity, d is size of an object and υ is the kinematic viscosity) and aspect ratio AR = 0.25 (where, AR = l/w, l is the length and w is the width of the rods). Different flow structures, power spectra analysis of lift coefficients and force statistics are studied for this analysis at small, moderate and large gap spacing. Findings: The present study revealed that the gap spacing between the rods has a great impact on the flow behaviour. Therefore, different flow patterns are observed and some of them are outlined as, i). Shear layer reattachment (SLR), ii). Semi developed single bluff body (SDSBB), iii). Fully developed vortex shedding (FDVS), iv). Semi developed irregular vortex shedding, v) Fully generated two row single bluff body, vi). Semi developed irregular single bluff body (SDISBB) and vii). Critical flow (CF) patterns. The critical flow behaviour is observed at the gap spacing (g1 , g2 ) = (5, 2.5), (here, g1 is the gap between upstream rods to middle one and g2 is the gap between middle rods to downstream rectangular rod). In force statistics analysis, the values of Cdmean and Strouhal number are computed at different spacing ratios. The value of mean drags coefficients for all three rodsat g1 = 3 is approximately same, but at g1 = 1 and 5, the maximum value of Cdmean is observed for C2 as compared to C1 and C3, that is 6.91. Furthermore, Strouhal number values are much less than the single rod (SR) value for all three chosen small, moderate and large gap spacing values. The maximum value of St is examined at (g1, g2) = (1, 1) i.e 0.19. Keywords: Drag Coefficient; Rectangular Rods, Single Relaxation Time Lattice Boltzmann Method, Vortex Shedding Suppression
Highlights
Fluid flow around more than one objects have attracted much attention in recent times due to its immense contribution in the field of engineering and industries
Islam et al [15] numerically examined the flow around three square rods with varied gap spacing and critical flow pattern was observed at g = 3
To study the flow behavior over rectangular rods at unequal gap spacing by taking g1 = 1, 3 and 5 and g2 = 0.5-7 with fixed Re = 150 and aspect ratio (AR) = 0.25, obtained results are classified into three different flow regimes, i) Small wake regime, ii) Moderate wake regime, iii) Large wake regime
Summary
Fluid flow around more than one objects have attracted much attention in recent times due to its immense contribution in the field of engineering and industries. As a result damaging of structures occurs In this regard, many experimental and numerical works has been done to overcome these noises using square/circular rods. An experimental study of large eddy simulation (LES) for flow past rectangular-section performed by [2] revealed different flow characteristics at side ratio 0.4d to 4d and Re = 105. Flow is assumed to be laminar and uniform They concluded that at the critical gap spacing of g = 5, drag coefficients approached its maximum value. In[11] conducted an experimental study on the flow around two circular rods arranged tandemly He noticed critical gap spacing at g = 3.5 with Re = 22000. Islam et al [15] numerically examined the flow around three square rods with varied gap spacing and critical flow pattern was observed at g = 3. In present study, we examined the effect of unequal gap spacing for flow past over three rectangular rods a fixed Re and AR
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
