A numerical study of linear and nonlinear kinematic models in fish swimming with the DSD/SST method

Tian, Fang-Bao

doi:10.1007/s00466-014-1116-z

Cited by 16 publications

(6 citation statements)

References 89 publications

(128 reference statements)

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“…The half thickness of the body is mathematically approximated bywhere l is the arc length along the mid-line of the body, and L is the body length which is a constant during the swimming. 49…”

Section: Methodsmentioning

confidence: 99%

“…where l is the arc length along the mid-line of the body, and L is the body length which is a constant during the swimming. 49 The motion of the fish body includes three parts as shown in Figure 1: the oscillation of the second and third link in the local coordinate system (θ 1 and θ 2 ), the translation of the mass center (r c ), and the body rotation around the mass center (θ c ). For simplicity, it is assumed the movement of each link in the local coordinate system is totally determined by the fish itself.…”

Section: Kinematic Model Of the Bionic Fishmentioning

confidence: 99%

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A numerical simulation of target-directed swimming for a three-link bionic fish with deep reinforcement learning

Zhu

Pang

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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An accurate and robust feedback control system is of great importance for bionic robotic fish to perform complex tasks. This work presents a numerical study of target-directed swimming for a three-link bionic fish with a feedback control system based on deep reinforcement learning (DRL). The simulation is achieved by using a hybrid method of the DRL method and the immersed boundary–lattice Boltzmann method (IB–LBM). This framework makes use of the high computational efficiency of the IB-LBM for the generation of massive motion data needed in the DRL training. The fish is first trained to swim towards a static target from random orientation and distance. The only information available to the fish is its orientation and distance from the target. It learns an accurate and subtle control policy after the training. Then the control policy is applied to a moving target. Even though the fish encounters some situations that never happened in the training, it can choose appropriate actions to follow the target in close proximity and automatically adapt its velocity with the velocity of the target. Those simulations demonstrate the accuracy, robustness of the control method, and its ability to adapt to new situations.

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Section: Methodsmentioning

confidence: 99%

Section: Kinematic Model Of the Bionic Fishmentioning

confidence: 99%

A numerical simulation of target-directed swimming for a three-link bionic fish with deep reinforcement learning

Zhu

Pang

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…The DSD/SST solver used in this work has been validated and applied to many problems including stationary, prescribed moving and FSI boundaries. 14,28,29,36,41,44,45,73 The structure solver was validated in Tian, 29 and the FSI solver was presented in literature. 29,30…”

Section: Dsd/sst Fsi Methodsmentioning

confidence: 99%

“…Therefore, it can be effectively applied to simulate complex flows and FSI problems where moving boundaries and interfaces are involved. [17][18][19] Since its birth, the DSD/SST method has been extensively used to model complex flows and FSI, such as animal swimming and flight, 29,30,[34][35][36][37][38][39][40][41][42][43][44][45] flag flapping, 2,3 and non-Newtonian flow. 28,46 Body-fitted grid methods could be time consuming and complicated due to the difficulties associated with grid generation in complex geometries and mesh movement/re-generation in large displacement/deformation problems.…”

Section: Introductionmentioning

confidence: 99%

Benchmark numerical solutions for two-dimensional fluid–structure interaction involving large displacements with the deforming-spatial-domain/stabilized space–time and immersed boundary–lattice Boltzmann methods

Jiang

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part C:

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Body-fitted and Cartesian grid methods are two typical types of numerical approaches used for modelling fluid–structure interaction problems. Despite their extensive applications, there is a lack of comparing the performance of these two types of approaches. In order to do this, the present paper presents benchmark numerical solutions for two two-dimensional fluid–structure interaction problems: flow-induced vibration of a highly flexible plate in an axial flow and a pitching flexible plate. The solutions are obtained by using two partitioned fluid–structure interaction methods including the deforming-spatial-domain/stabilized space–time fluid–structure interaction solver and the immersed boundary–lattice Boltzmann method. The deforming-spatial-domain/stabilized space–time fluid–structure interaction solver employs the body-fitted-grid deforming-spatial-domain/stabilized space–time method for the fluid motions and the finite-difference method for the structure vibrations. A new mesh update strategy is developed to prevent severe mesh distortion in cases where the boundary does not oscillate periodically or needs a long time to establish a periodic motion. The immersed boundary–lattice Boltzmann method uses lattice Boltzmann method as fluid solver and the same finite-difference method as structure solver. In addition, immersed boundary method is used in the immersed boundary–lattice Boltzmann solver to handle the fluid–structure interaction coupling. Results for the characteristic force coefficients, tail position, plate deformation pattern and the vorticity fields are presented and discussed. The present results will be useful for evaluating the performance and accuracy of existing and new numerical methodologies for fluid–structure interaction.

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“…Our DSD/SST package has also been validated and applied to several problems. 38,39,47,52,55,83,84 The structural package was validated in Ref. 39.…”

Section: Validation Of the Fsi Solvermentioning

confidence: 99%

An FSI solution technique based on the DSD/SST method and its applications

Tian

Wang

Young

et al. 2015

Math. Models Methods Appl. Sci.

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Communicated by T. E. TezduyarThis paper presents a fluid-structure interaction (FSI) solution technique in which the incompressible fluid dynamics involving moving boundaries is solved with the deformingspatial-domain/stabilized space-time (DSD/SST) method and the structural dynamics is solved with the finite difference (FD) method. The DSD/SST and FD solvers are coupled by an implicit partitioned coupling strategy based on staggered subiterations. Three types of relaxation are applied on the FSI surface velocity and hydrodynamic force. The first one is applied to delay the coupling conditions at the beginning of each simulation; the second one is applied to relax the increment during each subiteration; and the third one is applied to filter high frequency oscillations between each time step. A pitching plate in a uniform flow is calculated to validate the FSI technique. The present results are in good agreement with data predicted by other methods. In addition, two problems are calculated to demonstrate the capability of this solver: an orbital flow over flapping foil propulsion and energy harvesting and a flexible plate in a cavity excited by an external force. An FSI solution technique 3expense. The mesh moves following the immersed boundary motion every time step if moving boundaries are involved, and may be regenerated if the distortion of elements is severe. The advantage of these methods is that the boundary conditions can be directly imposed and thus it has high-order accuracy near the boundary. This treatment could be computationally expensive and complicated, especially for the cases involving complex geometries and large displacements/deformations. The DSD/SST method is one of the earliest space-time formulations for fluid dynamics simulations involving moving boundaries and interfaces. This method is based on stabilized finite element formulations written over the space-time domain of the fluid. In this method, the streamline-upwind/Petrov-Galerkin 42,43 and pressurestabilizing/Petrov-Galerkin 25,44 formulations are the stabilization strategies used to prevent numerical instabilities encountered in solving flow problems with high Reynolds number, high Mach number, shocks or strong boundary layers, and when using equal-order interpolation functions for both velocity and pressure. In addition, the DSD/SST method allows the spatial domain at various time levels to vary without introducing additional interpolation routines if the grid topology is preserved, and thus can be effectively applied to fluid dynamics computations involving moving boundaries and interfaces. 25-27 Since the work by Tezduyar et al. [25][26][27] the DSD/SST formulation has been extensively used to simulate problems involving moving boundaries and FSI. Some examples of these applications are animal swimming and flight, 39,45-55 flag flapping, 29,34 spacecraft parachutes, 56-68 cardiovascular fluid mechanics, 69-75 wind-turbine aerodynamics, 76-80 and non-Newtonian flow. 38,81 Some of these applications have been reported in two rece...

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A numerical study of linear and nonlinear kinematic models in fish swimming with the DSD/SST method

Cited by 16 publications

References 89 publications

A numerical simulation of target-directed swimming for a three-link bionic fish with deep reinforcement learning

A numerical simulation of target-directed swimming for a three-link bionic fish with deep reinforcement learning

Benchmark numerical solutions for two-dimensional fluid–structure interaction involving large displacements with the deforming-spatial-domain/stabilized space–time and immersed boundary–lattice Boltzmann methods

An FSI solution technique based on the DSD/SST method and its applications

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