INNOVATIVE ANALYSIS OF FLUID DYNAMICS AROUND MOVING BODIES USING THE IMMERSED BOUNDARY METHOD

Abstract

One of the key challenges in fluid mechanics is analyzing fluid flow around moving bodies. Traditional methods like computational fluid dynamics (CFD) require mesh generation around the body, which is especially time-consuming and tedious for moving objects. This paper presents a comprehensive investigation into the fluid flow behavior around a moving body across four distinct geometries. The Navier–Stokes equations were solved using the finite volume method and the semi-implicit method for pressure-linked equations algorithm, allowing seamless coupling of velocity and pressure fields. Additionally, the immersed boundary method (IBM) was employed to accurately represent the moving body within the fluid domain. The study began by verifying the flow between two parallel planes using three motion drives: mass-driven, pressure-driven, and body force–driven. Numerical simulations were conducted to verify the flow between two parallel planes using various motion drives, and stationary body simulations were performed at Reynolds numbers 20 and 40. Three different IBM approaches—feedback forcing, direct forcing, and the implicit velocity correction method—were employed. Four key scenarios were investigated: the free fall of an object within a vertical water-filled enclosure under gravity, the rotational motion of a rigid body within the fluid at a constant angular velocity, the linear motion of a rigid body with a user-controlled constant velocity, and the constrained movement of a rigid body within an enclosed fluid. The simulations, executed on a computer with a 3 GHz CPU and 16 GB RAM, each took approximately 10 hours. In contrast, utilizing the boundary fitting method (BFM) requires additional time to generate the mesh at each time step, thereby increasing the overall computation time. This research underscores the advantages of IBM over BFM in studying fluid–object interactions. By eliminating the need for gridding around the object, IBM achieves notably faster run times than conventional CFD and BFM methods, especially when analyzing flow around moving bodies. The proposed approach proves effective in solving flow dynamics around moving objects of arbitrary and complex shapes.