In order to determine artificial ventilated cavity shape and provide design reference for engineering applications, the shape of ventilated cavity and the drag of underwater body have been numerically simulated with c...In order to determine artificial ventilated cavity shape and provide design reference for engineering applications, the shape of ventilated cavity and the drag of underwater body have been numerically simulated with commercial code in this work. Empirical formulas between ventilated cavity shape and cavitation number are obtained under the conditions of zero incidence and similarity shapes of ventilated cavity and vapor cavity have been validated under the same cavitation number. In addition, the relations between change of cavitator incidence and cavity unsymmetry and the relations of between drag and cavity shape have been primarily analysed. Furthermore, the numerical results fit well with the experimental results.展开更多
The flow past various mechanical cavity, which is a common structure on the surface of the underwater vehicle, and generating hydrodynamic noise has attracted considerable attention in recent years. In this paper, a h...The flow past various mechanical cavity, which is a common structure on the surface of the underwater vehicle, and generating hydrodynamic noise has attracted considerable attention in recent years. In this paper, a hybrid method is presented to investigate the hydrodynamic noise induced by mechanical cavities with various shapes. With this method, the noise sources in the near wall turbulences or in the wake are computed by the large eddy simulation （LES） and the generation and propagation of the acoustic waves are solved by the Ffowcs Williams-Hawkings （FW-H） acoustic analogy method with acoustic source terms extracted from the time-dependent solutions of the unsteady flow. The feasibility and reliability of the current method was verified by comparing with experimental data （Wang, 2009）. The 2D cavity models with different cross-section shapes and 3D cavity models with different cavity mouth shapes （rectangular and circular） are developed to study the influence of cavity shape on the hydrodynamic noise. By comparing the flow mechanisms, wall pressure fluctuations, near-field and far-field sound propagation distributions, it is found that the quadrangular cavity with equal depths of leading-edge and trailing-edge is preferred for its inducing lower hydrodynamic noise than the cylindrical cavity does.展开更多
文摘In order to determine artificial ventilated cavity shape and provide design reference for engineering applications, the shape of ventilated cavity and the drag of underwater body have been numerically simulated with commercial code in this work. Empirical formulas between ventilated cavity shape and cavitation number are obtained under the conditions of zero incidence and similarity shapes of ventilated cavity and vapor cavity have been validated under the same cavitation number. In addition, the relations between change of cavitator incidence and cavity unsymmetry and the relations of between drag and cavity shape have been primarily analysed. Furthermore, the numerical results fit well with the experimental results.
基金supported by the Key Program of National Natural Science Foundation of China (Grant No. 50835006)the National Science and Technology Major Project of China (Grant No. 2008ZX05027-004-03)
文摘The flow past various mechanical cavity, which is a common structure on the surface of the underwater vehicle, and generating hydrodynamic noise has attracted considerable attention in recent years. In this paper, a hybrid method is presented to investigate the hydrodynamic noise induced by mechanical cavities with various shapes. With this method, the noise sources in the near wall turbulences or in the wake are computed by the large eddy simulation （LES） and the generation and propagation of the acoustic waves are solved by the Ffowcs Williams-Hawkings （FW-H） acoustic analogy method with acoustic source terms extracted from the time-dependent solutions of the unsteady flow. The feasibility and reliability of the current method was verified by comparing with experimental data （Wang, 2009）. The 2D cavity models with different cross-section shapes and 3D cavity models with different cavity mouth shapes （rectangular and circular） are developed to study the influence of cavity shape on the hydrodynamic noise. By comparing the flow mechanisms, wall pressure fluctuations, near-field and far-field sound propagation distributions, it is found that the quadrangular cavity with equal depths of leading-edge and trailing-edge is preferred for its inducing lower hydrodynamic noise than the cylindrical cavity does.
