A target-fixed immersed-boundary formulation for rigid bodies interacting with fluid flow

Lin, Tai-Chia; Hsieh, Hsin-Yu; Tsai, Hsieh-Chen

doi:10.1016/j.jcp.2020.110003

Cited by 4 publications

(1 citation statement)

References 35 publications

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“…In order to simulate the incompressible flow and perform resolvent analysis in the cylinder-fixed frame, the following incompressible vorticity equation and boundary conditions in the cylinder-fixed frame derived by Lin, Hsieh & Tsai (2021) are used: where and scaled respectively by and are the dimensionless laboratory-frame flow velocity and vorticity, is the plunging velocity described in § 2.1, is the unit vector in the streamwise direction and collects the external forcing inputs. In general, (2.2) can be extend to flows around a body undergoing any rigid-body motion by replacing with the combination of translational and rotational velocity of the motion.…”

Section: Problem Set-upmentioning

confidence: 99%

Flow control of a plunging cylinder based on resolvent analysis

Lin¹,

Tsai²,

Tsai³

2023

J. Fluid Mech.

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We design an open-loop active flow control for separated flows around a plunging circular cylinder based on resolvent analysis. The cylinder is plunging at a Strouhal number of 0.36 and a Reynolds number of 500. A linear time-periodic system for control is obtained by linearizing the non-inertial incompressible vorticity equation in the cylinder-fixed frame about a time-averaged base flow. Using the Lyapunouv–Floquet transformation, the linear time-periodic system is transformed into a similar linear time-invariant system, whose resolvent is analysed to obtain an optimal actuating Strouhal number of 0.1464 for the transformed linear system. Simulations show that the active control with tangential actuations is capable of reducing the lift fluctuation by up to 25.7 % when the flow is actuated near the predicted harmonic and subharmonic frequencies.

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Section: Problem Set-upmentioning

confidence: 99%

Flow control of a plunging cylinder based on resolvent analysis

Lin¹,

Tsai²,

Tsai³

2023

J. Fluid Mech.

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Modeling and Analyzing the Dynamical Motion of a Rigid Body with a Spherical Cavity

Farag

Amer

Abady

2022

J. Vib. Eng. Technol.

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The rotatory motion of a rigid body having a cavity, close to a spherical form, filled with a viscous incompressible fluid around its center of mass is investigated. It is assumed that the Reynolds number has a modest restricted value due to the high velocity of the fluid. The body rotates under the influence of a viscous fluid besides the action of a gyrostatic moment vector about the principal axes of the body. The governing system of motion is derived and the averaging of the Cauchy problem of this system is analyzed. The analytic solutions are derived through several transformations and plotted graphically to demonstrate the positive influence of the physical body's parameters on the motion. The stability of these solutions is examined through their phase plane diagrams. In light of the efficiency of a gyrostatic moment on the considered motion, new results of this work have been achieved. The significance of this work stems from its numerous uses in everyday life, particularly in vehicles that hold liquids, such as aircraft, submarines, ships, and other vehicles. Moreover, it is also used in engineering applications that depend on the gyroscopic theory.

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