On Flow Past a Supercavitating Cascade of Cambered Blades

1972 ◽  
Vol 94 (1) ◽  
pp. 163-168 ◽  
Author(s):  
C. C. Hsu
Keyword(s):  
Numerical Results ◽  
Points Of Interest ◽  
Flow Past ◽  
Supercavitating Flow ◽  
Linearized Theory ◽  
Flow Through

A linearized theory for supercavitating flow through a cascade of cambered blades is developed. Numerical results illustrating various points of interest are presented.

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.

Supercavitating Flow About a Slender Wedge in a Transverse Gravity Field

1963 ◽  
Vol 7 (03) ◽  
pp. 14-23
Author(s):  
R. L. Street
Keyword(s):  
Gravity Field ◽  
First Order ◽  
Flow Past ◽  
Supercavitating Flow ◽  
Linearized Theory

In this paper a linearized theory is developed for supercavitating flow past a slender strut or wedge in a transverse gravity field. The theory is expected to be valid when the effects of the gravity field are of first-order smallness consistent with the linearization approximations. The additional lift and moment forces acting on the strut as a result of the gravity field are calculated. The transverse gravity field is found to produce additional forces which should be considered in hydrodynamic design.

A Note on Gravity Effects in Supercavitating Flow

1965 ◽  
Vol 9 (01) ◽  
pp. 39-45
Author(s):  
R. L. Street
Keyword(s):  
Gravity Field ◽  
Quantitative Agreement ◽  
Cavitation Number ◽  
Number Range ◽  
First Order ◽  
Average Value ◽  
Flow Past ◽  
Supercavitating Flow ◽  
Gravity Effects ◽  
Linearized Theory

Two approximations to the linearized theory for supercavitating flow about slender bodiesare applied to the case of flow past a slender wedge in a transverse gravity field. The additional lift and moment forces arising as a result of the gravity field are calculated by theories that are expected to hold when the gravity effects are of first-order smallnessconsistent with the linearization appi'oximations. The lift and moment coefficients obtained from the two approximations are in general quantitative agreement over the most important cavitation-number range. The results obtained confirm the validity of the average-value approximation introduced by Parkin.

scholarly journals The Effect of a Longitudinal Gravitational Field on the Supercavitating Flow Over a Wedge

1961 ◽  
Vol 28 (2) ◽  
pp. 188-192 ◽  
Author(s):  
A. J. Acosta
Keyword(s):  
Gravitational Field ◽  
Drag Coefficient ◽  
Froude Number ◽  
Cavitation Number ◽  
Streamline Flow ◽  
Flow Past ◽  
Supercavitating Flow ◽  
Linearized Theory

The free-streamline flow past a symmetrical wedge in the presence of a longitudinal gravitational field is determined with a linearized theory. The proportions of the cavity depend upon the cavitation number and Froude number. The drag coefficient is likewise affected by gravity, though to a smaller extent.

Supercavitating Linear Cascades With Rounded Noses

1974 ◽  
Vol 96 (1) ◽  
pp. 35-42
Author(s):  
O. Furuya
Keyword(s):  
Singular Perturbation ◽  
Perturbation Method ◽  
Numerical Results ◽  
Singular Perturbation Method ◽  
Local Flow ◽  
Circular Arc ◽  
Linear Cascade ◽  
Pressure Distributions ◽  
Flow Past ◽  
Linearized Theory

A singular perturbation method is used to analyze the flow past a linear cascade of thin supercavitating hydrofoils which have rounded leading edges. This consists essentially of correcting the local flow near the nose as determined by a somewhat improved linearized theory so that pressure distributions can be calculated. Numerical results for a number of cases having circular arc camberline and elliptic noses are presented over a range of parameters suitable for pump or propeller configurations. Some of these show very good lift/drag ratios and pressure distributions even for larger stagger angles.

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.

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.

Prediction of Aeroacoustic Resonance in Cavities of Hole-Pattern Stator Seals

2010 ◽  
Author(s):  
David N. Liliedahl ◽  
Forrest L. Carpenter ◽  
Paul G. A. Cizmas
Keyword(s):  
Experimental Data ◽  
Flow Instability ◽  
Numerical Results ◽  
Navier Stokes ◽  
Empirical Constant ◽  
Freestream Velocity ◽  
Flow Solver ◽  
Eddy Simulation ◽  
Flow Past ◽  
Acoustic Instabilities

A Reynolds-averaged Navier-Stokes (RANS) solver developed in-house was used to simulate grazing channel flow past single and multiple cavities. The objective of this investigation was to predict fluid instabilities in hole-pattern stator seals. The numerical results generated with the RANS solver showed good agreement with those obtained using a commercial Large Eddy Simulation (LES) code. In addition, the numerical results agreed well with experimental data. Rossiter’s formula, a popular semi-empirical model used to predict frequencies of hole-tone acoustic instabilities caused by grazing fluid flow past open cavities, was modified using the RANS solver results to allow for its application to channel flows. This was done by modifying the empirical constant κ, the ratio of vortex velocity and the freestream velocity. The dominant frequencies predicted using the Rossiter’s formula with the new κ value matched well the experimental data for hole-pattern stator seals. The RANS solver accurately captured the salient features of the flow/acoustic interaction and predicted well the dominant acoustic frequencies measured in an experimental investigation. The flow solver also provided detailed physical insight into the cavity flow instability mechanism.

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