Numerical Study Of Cylindrical And Airfoil Vortex Induced Vibration Based On Slotted Flow Control

Vortex-induced vibration is a fluid-solid coupling phenomenon caused by flow instability,and it is common in practical engineering applications.Most actual engineering structures are bluff body structures,and their design ideas are mainly to resist working loads,including fluid flow and surface heat transfer surfaces.They are usually not designed to be streamlined based on aerodynamics,which makes the structure subject to flow-induced vibration The possibility of impact is greater.At the same time,the vortex-induced vibration generated by the laminar flow separation of the airfoil has a greater impact on the stability of the aircraft.Therefore,whether it is from the perspective of suppressing the vortex-induced vibration phenomenon or effectively using the vortex-induced vibration energy,it is very necessary to control the vortex-induced vibration of the cylinder.This article improves the traditional immersion boundary method.Through the introduction of virtual nodes and hybrid nodes,and the addition of smooth functions at the fluid-solid boundary,the numerical instability in the calculation process is reduced and the boundary motion process is eliminated.,Due to the non-physical vibration caused by the numerical error of the interpolation at the boundary of the immersion boundary method,based on the sharp boundary method proposed by Mittal,the speed processing and pressure processing of the mixed nodes are optimized,and the modified mixing is avoided The numerical error caused by the no divergence constraint of the node.Under the framework of self-programmed immersed boundary method,this paper takes slotted flow control as the starting point,and optimizes the flow control of the vortex-induced vibration of the cylinder and the pitching motion caused by the separation of airfoil laminar flow under specific conditions.With airfoil as the research object,improving the lift and drag characteristics of the flow around the cylinder and the wing and optimizing the flow field conditions are the goals,and the fluid-structure coupling characteristics brought by the control scheme are studied,and the optimal solution is found.Based on the CFD fluid-structure coupling calculation theory,the two-dimensional program code of the adaptive immersion boundary method is written,including the two-dimensional Cartesian grid division program,the core calculation program,the realization of multi-grid technology,and some postprocessing programs.On this basis,k-?,k-?,and k-? SST turbulence models are added to the program to distinguish and compare the accuracy of the simulation of vibration caused by flow separation in the case of large angles of attack of the wing at medium and low Reynolds numbers.Relying on the program,the cylinder and the wing are slotted,and the different slot width,slot angle,slot position and other parameters in the two cases are simulated respectively,and the slotted flow control scheme is analyzed and researched on the flow field and Under the influence of the force,the vortex-induced vibration effect under the influence of the structural dynamics equation and the influence of flow control on the displacement and deflection of the structure are analyzed at the same time.