Parametric design method for multiple period stable numerical wave-generation
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摘要:
目的 针对数值模拟中波浪随传播时间和距离发生波幅衰减及相位偏移的问题,提出一套可用于多周期稳定造波的参数设计方法。 方法 基于Navier-Stokes方程和流体体积(VOF)方法进行五阶Stokes波数值模拟,通过对一维波动方程的离散形式进行分析,研究几个重要参数对造波效果的影响。最后,应用所提参数设计方法对KCS船型在迎浪中的阻力和运动响应进行三维数值计算,并与模型实验结果进行比较。 结果 结果表明,将内迭代次数、网格分辨率、库朗数等参数按照一定规则设置,20个波周期内的波幅误差约5%,40个波周期的约10%。对KCS船型进行的三维数值计算结果与模型实验结果相比误差约10%。 结论 经此研究,验证了所提方法的可行性。 -
关键词:
- 数值造波 /
- Navier-Stokes方程 /
- 流体体积方法 /
- KCS /
- 波浪增阻
Abstract:Objective To address the problem of wave amplitude attenuation and phase shift with respect to propagation time and distance in numerical simulation, a set of parametric design methods that can stabilize wave generation in multiple periods is given. Methods Based on Navier-Stokes equations and volume of fluid (VOF) method, a numerical simulation of fifth-order Stokes wave is carried out. Through the analysis of the discrete scheme of the one-dimensional wave equation, the influence of several important parameters on wave-generation effect is studied. Finally, the proposed parametric design method is used to carry out the three-dimensional numerical calculation of the resistance and motion response of the KRISO container ship (KCS) in head seas. Results The results show that parameters such as inner iteration times, grid resolution, and Courant number can be accurately set according to certain rules to ensure that the error of wave amplitude is about 5% within 20 wave periods and about 10% within 40 wave periods. Through the three-dimensional numerical calculation of a KCS ship, the results obtained show an error of about 10% compared with the experimental results of model, Conclusion which verifies the feasibility of this method. -
Key words:
- numerical wave generation /
- Navier-Stokes equations /
- volume of fluid method /
- KCS /
- added resistance
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表 1 对照算例A0的参数设置
Table 1. Parameter setting of Case A0 for comparison
算例编号 波高H/m 波长λ/m 波陡H/λ 内迭代次数n 波高方向网格数NZ 网格长高比r 总网格数/万 σ A0 0.16 4 0.04 15 20 4 58 150 0.1 表 2 B1~B4算例参数设置
Table 2. Parameter setting for Case B1-B4
算例
编号波高
H/m波长
λ/m波陡
H/λ内迭代
次数n波高方向
网格数Nz网格
长高比r总网
格数/万σ B1 5 B2 8 B3 0.16 4 0.04 10 20 4 58 150 0.1 A0 15 B4 20 表 3 C1~C4算例参数设置
Table 3. Parameter setting for Case C1-C4
算例
编号波高
H/m波长
λ/m波陡
H/λ内迭代
次数n波高方向
网格数Nz网格
长高比r总网
格数/万σ A0 0.1 C1 0.2 C2 0.16 4 0.04 15 20 4 58 150 0.3 C3 0.4 C4 0.5 表 4 波高方向网格数影响算例参数设置
Table 4. Parameter setting of cases with different mesh number in the wave height
算例
编号波高
H/m波长
λ/m波陡
H/λ内迭代
次数n波高方向
网格数Nz网格
长高比r总网
格数/万σ D1 0.16 4 0.04 15 10 4 17 850 0.1 D2 16 36 650 A0 20 58 150 D3 25 84 950 D4 32 131 400 表 5 不同网格长高比算例参数设置
Table 5. Parameter setting for cases with different mesh aspect ratios
算例
编号波高
H/m波长
λ/m波陡
H/λ内迭代
次数n波高方向
网格数Nz网格
长高比r总网
格数/万σ E1.4 0.04 4 0.01 15 20 4 402 130 0.1 E1.8 8 213 980 E1.9 16 125 420 E2.4 0.08 4 0.02 15 20 4 200 810 0.1 E2.8 8 112 906 E2.16 16 65 552 E3.2 0.12 4 0.03 15 20 2 128 754 0.1 E3.4 4 69 176 E3.8 8 41 482 E3.16 16 24 060 E4.2 0.16 4 0.04 15 20 2 103 886 0.1 E4.4 4 58 140 E4.8 8 33 176 E4.16 16 19 662 E5.1 0.20 4 0.05 15 20 1 161 660 0.1 E5.2 2 85 168 E5.4 4 45 076 E5.8 8 24 960 E5.16 16 14 422 E6.1 0.24 4 0.06 15 20 1 127 082 0.1 E6.2 2 66 568 E6.4 4 35 292 E6.8 8 19 666 E7.1 0.28 4 0.07 15 20 1 112 634 0.1 E7.2 2 58 340 E7.4 4 31 612 表 6 CFD与EFD计算结果对比
Table 6. Comparison of calculation results by CFD and EFD
EFD CFD 误差/% TF3 0.055 0.053 −4.033 TF5 0.038 0.034 −10.484 σaw 2.725 2.577 −5.416 -
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