Analysing the Effect of Unequal Gap Spacing for Flow Past Over Three Rectangular Rods a Fixed Re (Reynolds Number) and Aspect Ratio (AR) | Chapter 2 | Mathematics and Computer Science: Contemporary Developments Vol. 2

 

Objectives: The present study examines the effect of unequal gap spacing for flow past over three rectangular rods a fixed Re (Reynolds number) and an Aspect Ratio (AR).

 

Background: In computational fluid dynamics, the numerical study of flow past over a single or more than one object has a great impact on the scientific community for suitable selection of parameters such as Reynolds number, gap spacing, and Aspect ratio. Their suitable choice is used to control flow for the purpose of saving energy in order to avoid damaging of structure by reducing the fluid forces and to suppress the vortex shedding.

 

Methodology: A two-dimensional (2-D) numerical study of flow over three rectangular Rods is conducted by using the Single Relaxation Time Lattice Boltzmann Method (SRTLBM). The gap spacing ( g ) between the rods is varied from 0.5 to 7 with a fixed Reynolds number i.e., Re = 150(Re = U ∞ d/v), (where U∞ is uniform velocity, d is the size of an object and v is the kinematic viscosity) and aspect ratio AR = 0.25 (where, AR = 1/w,1 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.

 

Results: The present study revealed that the gap spacing between the rods has a great impact on the flow behavior. 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 behavior 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). The power spectrum analysis of large wake regimes of different flow patterns showed distortion. Irregularities, multiple peaks and in some cases secondary peaks are also observed. Multi-peaks represent irregular behavior. While secondary peaks and distortion enable us to conclude that a critical flow pattern has been observed at certain points. In force statistics analysis, the values of Cdmean and Strouhal number are computed at different spacing ratios. The value of mean drag coefficients for all three rods at g1=3 is approximately the same, but at g1=1 and 5, the maximum value of Cdmean is observed for C2 as compared to C1 and C3, which 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. The amplitude of the values of the Strouhal number varied with the increase in the gap spacing. At critical flow, the Strouhal number has primary and secondary peaks, which depict the unsteadiness in the flow.

 

Author(s) Details

Shams-Ul Islam
Department of Mathematics, Comsats University Islamabad, Islamabad, 44000, Pakistan.

R. Manzoor
Department of Mathematics, SBK Women's University, Quetta, Pakistan.

M. Zahid
School of Mathematics and Statistics, Zhengzhou University, China.

S. Kulsoom
Department of Mathematics, SBK Women's University, Quetta, Pakistan.

U. Kausar
Department of Mathematics, SBK Women's University, Quetta, Pakistan.

 

Please see the book here:- https://doi.org/10.9734/bpi/mcscd/v2/852

 

Flow over a Rotationally-Oscillation Circular Cylinder and Around Two Cylinder Side by Side with Different Movements | Chapter 6 | Fundamental Research and Application of Physical Science Vol. 8

This work has two main goals: the analysis of the flow movement, as well as the behavior of the drag cooperative, around a circular barrel with rotationally-swinging. And, the study of the influence of different movements, of two next to each other cylinders, on the drag and pressure coefficients. First, a wide range of compelling frequencies, , and three principles of oscillation amplitudes, , are thought-out to analyze the flow dynamics for one vorticity contours. It is important to specify those others investigators for rotationally seesaw case did not capture the 2C mode of whirlpool shedding, noticed in the present study. Second, appropriate parameters of the flow around two circular cylinders organized side by side, accompanying four combinations of varying motions are presented. All cases are acted for =1000, amplitude of oscillation ( ) effective 3, frequency percentage ( ) of 0.5, specific turn  equal to 0.5 and different principles of spacing percentage . The combination of the type of campaign, together with the position of one barrel in relation to the different, exerts meaningful influence on the pressure distribution around the barrel surface and on the average values of the drag cooperative. The smallest profit of the average pressure coefficient ( =- 3.3), is got for the oscillating cylinder when established side by side accompanying the clockwise turn cylinder, case 3 and . On the other hand, the lowest mean drag cooperative , is obtained for the barrel with circling rotation, located in the lower position concerning oscillating barrel in the upper position, accompanying spacing middle from two points them of 1.5. Furthermore, the rotation change is more effective in lowering drag than the rotation-fluctuation movement, for the studied commonness ratio.

Author(s) Details:

Alice Rosa da Silva,
Faculty of Civil Engineering, Federal University of Uberlândia, Uberlândia-MG, Brazil.

Bruno de Oliveira Lázaro,
Faculty of Civil Engineering, Federal University of Uberlândia, Uberlândia-MG, Brazil.

Please see the link here: https://stm.bookpi.org/FRAPS-V8/article/view/11675

Aerodynamic Characterization of Bio Inspired Corrugated Wings: A Recent Study | Chapter 8 | New Visions in Science and Technology Vol. 8

 Corrugations on the surface of a dragon fly's wings in the natural are known to have efficient aerodynamic qualities. This study used a 2-D panel approach and wind tunnel testing to evaluate the aerodynamics of bio-inspired profiles corrugated A, corrugated B, and NACA 0010. For two Reynolds numbers, 1.9x104 and 1.5x105, and angles of attack ranging from 0 to 160 degrees, all profiles were tested for coefficient of lift, drag, and glide ratio. Using current and past experiment data, as well as computational work from the cited literature, the panel approach's results have been confirmed. There was considerable agreement between the experimental and panel techniques at low angles of attack. The results revealed that corrugated profiles may produce higher lift coefficient and lower drag coefficient up to 80 degrees angles of attack when compared to NACA 0010. The panel approach was used to validate the surface pressure coefficients for all three profiles at 40 angles of attack. Non-dimensional pressure and velocity contours are displayed from -100 to 200 degrees of attack. According to a high agreement between experimental data and computational methodologies, corrugated profiles outperform NACA 0010 for low Reynolds number flows.

Author(S) Details

Yagya Dutta Dwivedi
Institute of Aeronautical Engineering, India.

View Book:- https://stm.bookpi.org/NVST-V8/article/view/4835