Efficient Immersed Boundary Method for Strong Interaction Problem of Arbitrary Shape Object with the Self-Induced Flow

AbstractWe study the settling of solid particles in a viscous incompressible fluid contained within a two-dimensional channel, where the mass density of the particles is greater than that of the fluid. The fluid-structure interaction problem is simulated numerically using the immersed boundary method, where the added mass is incorporated using a Boussinesq approximation. Simulations are performed with a single circular particle, and also with two particles in various initial configurations. The terminal particle settling velocity and drag coefficient correspond closely with other theoretical, experimental and numerical results, and the particle trajectories reproduce the expected behavior qualitatively. In particular, simulations of a pair of interacting particles similar drafting-kissing-tumbling dynamics to that observed in other experimental and numerical studies.

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Simulating Pulsatile Flows Through a Pipe Orifice by an Immersed-Boundary Method

Journal of Fluids Engineering ◽

10.1115/1.1845554 ◽

2004 ◽

Vol 126 (6) ◽

pp. 911-918 ◽

Cited By ~ 4

Author(s):

Alexander Yakhot ◽

Leopold Grinberg ◽

Nikolay Nikitin

Keyword(s):

Immersed Boundary Method ◽

Pressure Difference ◽

Viscous Incompressible Fluid ◽

Immersed Boundary ◽

Recirculation Bubble ◽

Boundary Method ◽

Pulsatile Flows ◽

Bubble Length ◽

Flow Through ◽

Induced Flow

A pulsatile laminar flow of a viscous, incompressible fluid through a pipe with a sudden constriction (an orifice) was simulated by an immersed-boundary method. A fluid is forced to move by an imposed sinusoidally varying pressure difference, Δpt. For a pulsatile flow through a pipe orifice, an oscillating recirculation bubble develops behind the orifice. The induced flow rate, Qt, the recirculation bubble length, Lbt, as well as their phase shift ϕQ,ϕL with respect to the imposed pressure difference were computed for different constriction ratios and the Womersley Ws number.

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Mechanisms influencing the efficiency of aquatic locomotion

Modern Physics Letters B ◽

10.1142/s0217984918502998 ◽

2018 ◽

Vol 32 (25) ◽

pp. 1850299 ◽

Cited By ~ 1

Author(s):

Dong Zhang ◽

Guang Pan ◽

Liming Chao ◽

Guoxin Yan

Keyword(s):

Velocity Component ◽

Immersed Boundary Method ◽

The Self ◽

Immersed Boundary ◽

Lateral Velocity ◽

Number Range ◽

Aquatic Locomotion ◽

Boundary Method ◽

St Number

The optimal aquatic locomotion has previously been associated with a narrow St(= fA/u) number range of 0.2–0.4. We present how animals tune their Strouhal (St) number to this range to reveal the mechanisms influencing efficiency. The self-propelled swimming of a 2D swimmer is simulated using an immersed boundary method. The locomotion kinematics is controlled by two variables, [Formula: see text] and frequency f. We show that only when animals constrain their [Formula: see text] = 0.125–0.25, their St number can fall into the optimal St range. When [Formula: see text] Hz, the St number is independent with frequency. Although different combinations of f and [Formula: see text] can achieve a same cruising velocity, high-f and low-[Formula: see text] motions are more efficient. This can be linked to its larger lateral velocity component in the proto-vortex region and the transition of the tail vortices into small eddies.

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