Abstract
Modelling of unidirectional and oscillatory flows around a cylinder near a wall using an overlapping grid system is carried out. The circular grid system of the cylinder was overlapped with the rectangular grid system of the wall. The use of such an overlapping grid system is intended to reduce the CPU time compared to the cloud scheme in which vortex-to-vortex interaction is used, i.e., especially in calculating the shedding vortex velocity, since calculating the vortices velocity takes the longest CPU time. This method is not only time efficient, but also gives a better distribution of surface vorticity as the scattered vortices around the body are now concentrated on a grid point. Therefore, grid-to-grid interaction is used instead of vortex-to-vortex interaction. Velocity calculation was also carried out using this overlapping grid in which the new incremental shift position was summed up to obtain the total new vortices position. The engineering applications of this topic are to simulate the loading of submarine pipeline placed close to the seabed or to simulate the flow as a result of the scouring process below the cylinder since there is space for the fluid to flow beneath it. The in-line and transverse force coefficients are found by integrating the pressure around the cylinder surface. The flow patterns are then obtained and presented. The comparison of the results with experimental evidence is presented and the range of good results is discussed.
Highlights
Various studies involving cylinders in close proximity to an impermeable surface have been conducted using computers and laboratories in the last five decades
The polar grid nodes are used to evaluate the interaction among vortices shed from the cylinder while the rectangular grid nodes are used to evaluate the influence of wall to the vortices
A of sumresults for the force coefficients of a cylinder placed at various distances from the wall with mary of the results for the force coefficients of a cylinder placed at various distances from a Reynolds number of 100,000 is shown in Table effect of theThe variation of the the the wall with a Reynolds number of 100,000 is shown in The
Summary
Various studies involving cylinders in close proximity to an impermeable surface have been conducted using computers and laboratories in the last five decades. The flows around two cylinders in close proximity under the influence of the initial conditions using a finite element-based program at low Reynolds numbers, have been investigated [3]. The vibration of a cylinder near a wall using a partition iterative scheme was studied based on the Petrov–Galerkin formulation [6] This was carried out to simulate flow past a freely vibrating circular cylinder placed in proximity to a stationary plane wall. The wall proximity effect on vortex-induced vibration (VIV) of an elastically mounted circular cylinder with 2D were systematically studied in two-dimension laminar flow at low Reynolds number. This condition was investigated by exposing a cylinder, placed near a wall, to an oscillatory flow and the span-wise correlation was calculated based on the cylinder surface This investigation indicated that the effect of wall proximity is insignificant, especially when the fluctuations in surface pressure are taken into consideration. The force coefficients can be calculated through the use of the Blasius equation by directly substituting and integrating the complex potential around the cylinder
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
