Numerical investigation of oscillation frequency and amplitude effects on the hydrodynamic coefficients of a body with NACA0012 hydrofoil section

Shojaeefard, Mohammad Hassan; Khorampanahi, A.; Mirzaei, Mojtaba

doi:10.1007/s12206-017-0422-8

Cited by 6 publications

(3 citation statements)

References 22 publications

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“…Therefore, not each branch network will reach the maximum number of training step. In this paper, we choose the flow field data of the NACA0012 airfoil (26) in the subsonic and wide range of angle of attack to study, which is under the calculation condition of Mach number 0.3, Reynolds number 6.98e6, and the range of angle of attack is −10 •~1 0 • , whose interval is 0.1 • . Table 1 shows the distribution of samples.…”

Section: Resultsmentioning

confidence: 99%

Flow field reconstruction method based on array neural network

Yuqi

et al. 2020

Aeronaut. j.

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Multi-dimensional aerodynamic database technology is widely used, but its model often has the curse of dimensionality. In order to solve this problem, we need projection to reduce the dimension. In addition, due to the lack of traditional method, we have improved the traditional flow field reconstruction method based on artificial neural networks, and we proposed an array neural network method. In this paper, a set of flow field data for the target problem of the fixed Mach number is obtained by the existing CFD method. Then we arrange all the sampled flow field data into a matrix and use proper orthogonal decomposition (POD) to reduce the dimension, whose size is determined by the first few modals of energy. Therefore, significantly reduced data are obtained. Then we use an arrayed neural network to map the flow field data of simplified target problem and the flow field characteristics. Finally, the unknown flow field data can be effectively predicted through the flow field characteristic and the trained array neural network. At the end of this paper, the effectiveness of the method is verified by airfoil flow fields. The calculation results show that the array neural network can reconstruct the flow field of the target problem more accurately than the traditional method, and its convergence speed is significantly faster. In addition, for the case of high angle flow field, the array neural network also performs well. There are no obvious jumps, and huge errors are found in results. In general, the proposed method is better than the traditional method.

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Section: Resultsmentioning

confidence: 99%

Flow field reconstruction method based on array neural network

Yuqi

et al. 2020

Aeronaut. j.

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“…The hydrodynamic coefficients of a moving body with NACA0012 hydrofoil utilizing CFD are calculated, and the relationship between oscillation frequency, amplitude, and hydrodynamic coefficients is discussed in [25].…”

Section: Introductionmentioning

confidence: 99%

The Hydrodynamic Coefficient Analysis and Motion Control of the Lingyun Moveable Lander

Zhang

2021

Geofluids

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A moveable lander has the advantages of low cost and strong controllability and is gradually becoming an effective autonomous ocean observation platform. In this study, the hydrodynamic property of the Lingyun moveable lander, which has completed experiments in the Mariana Trench in 2020, is analyzed with the semiempirical method and computational fluid dynamic (CFD) method. We calculate the inertial hydrodynamic coefficients and viscous hydrodynamic coefficients of the lander. The results show that the CFD can provide the hydrodynamic property for the moveable lander’s design. The dynamic equations and kinematic equations are completely constructed combined with the hydrodynamic coefficients. Subsequently, this paper utilized the PID control method and S control method to control the motions of the lander. The simulation results show that the methods accurately follow the preplanned path.

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“…[10][11][12][13][14] Although this method is most effective, it has failed to become widely popular because of its long test periods and high cost. With the development of computer technology and computational fluid dynamics (CFD) technology, numerical simulation [15][16][17] with short cycles, low cost, and manpower savings has become a new method for determining hydrodynamic coefficients. Recently, this method has been widely used to achieve research results.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic calculation and analysis of a complex-shaped underwater robot based on computational fluid dynamics and prototype test

Tao

Sun

et al. 2017

Advances in Mechanical Engineering

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In this article, a mathematical model of hydrodynamic force was established to model the influence of wall in realizing the precise control and maneuverability of a complex-shaped underwater robot. A hydrodynamic model of a robot for use in a nuclear reaction pool was presented containing not only hydrodynamics coefficients but also a wall hydrodynamic force term, which was often ignored for robots used at sea. First, hydrodynamic coefficients in the model, including viscous and inertial coefficients, were solved by simulating steady-state and unsteady-state motion by computational fluid dynamics. Next, the wall hydrodynamic force was calculated by computational fluid dynamics for different velocities and distances from the wall, and the scope of influence of the wall was identified. Finally, hydrodynamic coefficients without the wall effect and with the wall hydrodynamic force under different conditions were measured experimentally in a circulating water tank. The result demonstrated the accuracy of hydrodynamic calculation by computational fluid dynamics and verified the reliability of the hydrodynamic mathematical model.

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Numerical investigation of oscillation frequency and amplitude effects on the hydrodynamic coefficients of a body with NACA0012 hydrofoil section

Cited by 6 publications

References 22 publications

Flow field reconstruction method based on array neural network

Flow field reconstruction method based on array neural network

The Hydrodynamic Coefficient Analysis and Motion Control of the Lingyun Moveable Lander

Hydrodynamic calculation and analysis of a complex-shaped underwater robot based on computational fluid dynamics and prototype test

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