Effect of a “slip” splitter plate on vortex shedding from a cylinder

2003 ◽  
Vol 15 (3) ◽  
pp. 817-820 ◽  
Author(s):  
S. Mittal
2013 ◽  
Author(s):  
Mohammad Javad Emamgholizadeh ◽  
Ahmad Reza Mostafa Gharabaghi ◽  
Karim Abedi ◽  
Mohammad Hossein Sedaaghi

Pipeline is an appropriate method for transmission of oil and gas from seabed hydrocarbon reservoir to the land and platform or any other place where it is needed. Free spans in the line may occur initially by an uneven seabed or be created later due to under-scouring. Vortex Induced Vibration (VIV) may occur in these free spans at high Reynolds’ numbers. Resonance can occur if the frequency of vortex shedding is close to the pipeline’s natural frequency. Otherwise, it can cause pipeline’s fatigue leading to its breakage and consequently economical and environmental losses. In literature, different methods are presented for decreasing the scouring depth due to the vortex shedding. One of them is the application of splitter plate. In this paper, the effect of splitter plate’s angle with horizon (α) on the vibrating behavior of pipeline with two degrees of freedom over an erodible bed is studied experimentally. The experiments were performed for reduced velocity in the range of 2.45–5.06 and gap ratio of zero. Image processing technique as a non-contact method is used for measuring the vibrations of cylinder. Experimental results indicate that the splitter plate’s angle is an important factor on the cylinder’s vibration amplitude. According to these results, for the angle in the range of 0 ≤ α ≤ 30, the vibration amplitude is decreased while its frequency is increased, but the results are vice versa for the range of 60 ≤ α ≤ 90.


Author(s):  
Minter Cheng

Fluid flow across a bluff body can induce a series alternating vortices in the downstream flow field. The vortex flow can produce adverse effects on many engineering applications. A number of studies have shown that the wake splitter plate is one of the means to stabilize the vortex formation process. However, most of the previous studies are confined to cylinders with attached splitter plates. Very few studies investigate the effects of the spacing between the cylinder and the splitter plate on the formation of wake vortices. In the present study, the effects of the splitter plate length as well as the gap distance between the splitter plate and the cylinder on the wake flow behind a cylinder have been studied experimentally for low Reynolds number of 400. Both circular and square cylinders are studied in this research. Four splitter plates with different length, 1 ≤ L/D ≤ 4, have been used and a range of cylinder and splitter plate gap distance, 0 < G/D < 6, have been studied. By using flow visualization technique and hot-film anemometer measurement, detailed measurements of the velocity distribution, the vortex shedding frequency, the wake width, and the wake formation length are carried out in order to get a clear understanding of the flow interference behavior. The experimental results indicate that splitter plates alter the vortex formation process in the wake causing a decrease in vortex shedding frequency. The Strouhal number decreases with increasing the splitter plate length as well as the gap distance between the cylinder and the splitter plate. It is shown that a jump in Strouhal number occurs at G/D of 3 to 6. The jump is splitter plate length dependent, and generally the gap distance at which jump takes place increases as the splitter plate length increases.


2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Ali Ahmed ◽  
Abdul Wahid ◽  
Raheela Manzoor ◽  
Noreen Nadeem ◽  
Naqib Ullah ◽  
...  

Numerical simulations are carried out to study the flow around two tandem square cylinders (SC) under the effect of spacing ratio(g/D) and splitter plate length (l/D) for a fixed Reynolds number (Re) = 100. The g/D is varied from 0 to 10 and l/D is varied from 0.5 to 10. The splitter plate length is found to have strong effect on vortex shedding and fluid forces. The maximum reduction in mean drag coefficient is observed at l/D = 8, that is 15% and 78% for upstream and downstream cylinders, respectively. The maximum reduction in root-mean-square value of lift coefficient is found at l/D = 10, that is 99%. The flow pattern at both of these points is steady flow. There is 100% vortex shedding suppression for l/D > 5. The observed flow patterns for flow past tandem cylinders without splitter plate are; single bluff body (SBB), steady flow (SF), quasi-steady flow (QSF), fully developed flow (FDF) and fully developed two-row vortex street flow (FDTRVS) regimes. SBB, QSF and SF regimes were observed in presence of splitter plate.


Author(s):  
Jinmo Lee ◽  
Donghyun You

Integrated computational fluid dynamics (CFD) and computational structural dynamics (CSD) simulations of flow over a cylinder with a flexible splitter plate attached to the rear stagnation point, are performed. Flow over a cylinder produces vortex shedding, which causes unsteady pressure and shear stress distributions over a flexible splitter plate. As a result, the flexible splitter plate vibrates with distinct frequencies, which are different from the vortex-shedding frequency and natural frequencies of the plate. A systematic and detailed analysis of the effects of the flexible plate on fluid-structure dynamics and on the drag and lift of the cylinder, is presented.


Sign in / Sign up

Export Citation Format

Share Document