Computed Transient Supercavitating Flow over A Projectile.(Dept.M)

2021 ◽  
Vol 26 (2) ◽  
pp. 79-91
Author(s):  
Nabil Mostafa
Keyword(s):  
Supercavitating Flow

Numerical Simulation Study on High-Temperature Ventilated Cavitating Flow Considering the Compressibility of Gases

2012 ◽  
Vol 569 ◽  
pp. 395-399
Author(s):  
Jing Zhao ◽  
Guo Yu Wang ◽  
Yan Zhao ◽  
Yue Ju Liu
Keyword(s):  
Numerical Simulation ◽  
State Equation ◽  
Field Structure ◽  
Cavitating Flow ◽  
Simulation Approach ◽  
Gas Velocity ◽  
Simulation Data ◽  
Ventilated Cavity ◽  
Supercavitating Flow ◽  
Fluctuation Range

A numerical simulation approach of ventilated cavity considering the compressibility of gases is established in this paper, introducing the gas state equation into the calculation of ventilated supercavitating flow. Based on the comparison of computing results and experimental data, we analyzes the differences between ventilated cavitating flow fields with and without considered the compressibility of gases. The effect of ventilation on the ventilated supercavitating flow field structure is discussed considering the compressibility of gases. The results show that the simulation data of cavity form and resistance, which takes the compressibility of gases into account, accord well with the experimental ones. With the raising of ventilation temperature, the gas fraction in the front cavity and the gas velocity in the cavity increase, and the cavity becomes flat. The resistance becomes lower at high ventilation temperature, but its fluctuation range becomes larger than that at low temperature.

Experiments on Gravity Effects in Supercavitating Flow

1966 ◽  
Vol 10 (02) ◽  
pp. 119-121
Author(s):  
T. Kiceniuk ◽  
A. J. Acosta
Keyword(s):  
Gravitational Field ◽  
Froude Number ◽  
Flow Past ◽  
Supercavitating Flow ◽  
Gravity Effects

Experiments on the effect of a transverse gravitational field on the supercavitating flow past a wedge tend to confirm predictions based on linearized free-streamline theory. A small though systematic dependence upon Froude number not accounted for by the existing theory is revealed, however.

A Validation Study of the Mixed-Foil Concept for High-Speed Hydrofoils

1976 ◽  
Vol 20 (02) ◽  
pp. 85-94
Author(s):  
D. P. Wang ◽  
Young T. Shen
Keyword(s):  
Validation Study ◽  
High Speed ◽  
High Speeds ◽  
Supercavitating Flow ◽  
The Future

A hydrodynamic validation study of the concept of the mixed foil has been conducted. A mixed foil is a streamlined hydrofoil equipped with a flap or other device which, above a certain speed, can be activated so as to change the flow around the foil into a supercavitating flow. At take-off and at moderate speeds, a mixed foil is operated as a subcavitating foil; at high speeds, it is operated as a supercavitating foil. During high-speed operations, a reduction in the wetted planform area of a mixed foil is proposed. The present study produces a design outline for the mixed foil and identifies essential problems which should be studied in the future. The analysis is illustrated by using hydrofoils with plano-convex sections. The lift-to-drag ratios at takeoff and at 45-knot and 83-knot cruising speeds are obtained.

A linearized theory for rotational supercavitating flow

1963 ◽  
Vol 17 (4) ◽  
pp. 513-545 ◽  
Author(s):  
Robert L. Street
Keyword(s):  
Shear Flow ◽  
Flow Past ◽  
Supercavitating Flow ◽  
Harmonic Perturbation ◽  
Two Dimensional Flow ◽  
Slender Bodies ◽  
Linearized Theory ◽  
Particular Solution ◽  
Effects Of Rotation ◽  
Rotational Problem

In this paper methods are given for establishing qualitative and quantitative measures of the effects of rotation in supercavitating flows past slender bodies. A linearized theory is developed for steady, two-dimensional flow under the assumption that the flow has a constant rotation throughout. The stream function of the rotational flow satisfies Poisson's equation. By using a particular solution of this equation, the rotational problem is reduced to a problem involving Laplace's equation and harmonic perturbation velocities. The resulting boundary-value problem is solved by use of conformal mapping and singularities from thinairfoil theory. The theory is then applied to asymmetric shear flow past wedges and hydrofoils and to symmetric shear flow past wedges. The presence of rotation is shown to create significant changes in the forces acting on the slender bodies and in the shape and size of the trailing cavities.

Spatio-Temporal Development of Supercavitation Over an Impulsively Launched Projectile

2006 ◽  
Author(s):  
C. J. Weiland ◽  
P. P. Vlachos
Keyword(s):  
High Speed ◽  
Temporal Development ◽  
Two Phase ◽  
Time Resolved ◽  
Gas Gun ◽  
Supercavitating Flow ◽  
Image Velocimetry ◽  
Spatio Temporal ◽  
Asymmetric Vortices ◽  
First Time

Supercavitation inception and formation was studied over blunt projectiles. The projectiles were fired using a gas gun method. In this method, projectiles are launched under the action of expanding detonation gases. Both qualitative and quantitative optical flow diagnostics using high speed digital imaging were used to analyze the spatio-temporal development of the supercavitating flow. For the first time, quantification of the supercavitation was achieved using Time Resolved Digital Particle Image Velocimetry (TRDPIV) detailing the two phase flow field surrounding the translating projectiles and the gas vapor bubble. Experimental results indicate that the supercavity forms at the aft end of the projectile and travels forward along the direction of projectile travel. The impulsive start of the projectile generates two asymmetric vortices which are shed from the blunt nose of the projectile. The vortices interact with the moving cavity and subsequently deform. This interaction is believed to directly contribute to the instabilities in the flight path.

CFD-based numerical study on the ventilated supercavitating flow of the surface vehicle

2020 ◽  
Vol 214 ◽  
pp. 107726 ◽  
Author(s):  
Hai An ◽  
Peng Sun ◽  
Hang Ren ◽  
Zhenyu Hu
Keyword(s):  
Numerical Study ◽  
Supercavitating Flow

Theory for Supercavitating Flow Through an Arbitrary Form Hydrofoil

1964 ◽  
Vol 86 (2) ◽  
pp. 285-290
Author(s):  
R. O¯ba
Keyword(s):  
Pressure Distribution ◽  
Arbitrary Form ◽  
Supercavitating Flow ◽  
Flow Through

An accurate theory which included the following two methods was developed concerning the flow through an arbitrary form supercavitating hydrofoil: (i) A method by which to obtain the hydrofoil form for a given pressure distribution; (ii) a method by which to estimate hydrofoil characteristics. The accuracy of the previously reported linearized solution was checked on, and then a very simple effective correcting method for the linearized solution was found out.

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