基于OU-高斯过程的推进器宽带激励谱模型

Broadband Excitation Spectrum Model of Thruster Based on OU-Gaussian Process

  • 摘要: 【目的】推进器激励信息是舰艇声振预报和调控的重要输入参数,为此本文提出了湍流诱导的推进器非定常宽带激励的OU-高斯广义表征模型。【方法】基于Ornstein-Uhlenbeck随机过程理论和叶元体理论,推导泵喷转子宽带激励的功率谱的近似解析模型。采用Sobol全局灵敏度分析获得模型参数的作用频段及其影响规律,并通过CFD计算结果验证了模型合理性和泛用性。【结果】结果显示,提出的广义表征模型能准确捕捉非定常激励功率谱中的宽带衰减特性与驼峰特征。该模型对参数具有很强的频率依赖性,其中,表征OU过程的部分参数作用频段较宽,而决定高斯函数的各参数作集中作用于驼峰附近频段。在对泵喷推进器推力功率谱的描述上,广义表征模型与CFD结果表现出一致性,模型的合理性和泛用性可从统计学置信区间角度得以验证。【结论】提出的广义表征模型可为舰艇声振调控提供一种简洁可靠的经验谱输入条件。模型也可为推进器非定常激励的反演识别提供先验信息约束,以减轻反问题的病态性并提高识别精度。

     

    Abstract: Objectives Propulsion excitation information is an important input parameter for predicting and controlling ship acoustic vibrations. Therefore, this paper proposes an OU Gaussian generalized characterization model for turbulence induced unsteady broadband excitation of propellers. Methods An approximate analytical model for the power spectrum of broadband excitation in pump-jet rotors is derived based on the Ornstein-Uhlenbeck stochastic process theory and blade element theory. Sobol global sensitivity analysis is used to identify the operating frequency ranges and influence patterns of model parameters, and CFD results validate the model’s rationality and generality. Results The proposed generalized characterization model accurately captures the broadband attenuation characteristics and hump features in the power spectrum of non-stationary excitation. The model parameters exhibit strong frequency dependence; parameters characterizing the OU process operate over a wide frequency range, while parameters determining the Gaussian functions focus on frequencies near the hump. The generalized characterization model shows consistency with CFD results in describing the thrust power spectrum of a pump-jet thruster, and its rationality and generality are validated from a statistical confidence interval perspective. Conclusions The proposed generalized characterization model provides a simple and reliable empirical spectrum input for the acoustic and vibration control of ships. It also offers prior information constraints for the inversion and identification of non-stationary excitation in thrusters, mitigating the ill-posedness of inverse problems and improving identification accuracy.

     

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