Axisymmetric Cavity Flows Past Slender Bodies of Revolution

1974 ◽  
Vol 8 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Y. S. Chou
Keyword(s):  
Cavity Flows ◽  
Bodies Of Revolution ◽  
Axisymmetric Cavity ◽  
Slender Bodies

An analytical solution for two slender bodies of revolution translating in very close proximity

2007 ◽  
Vol 582 ◽  
pp. 223-251 ◽  
Author(s):  
Q. X. WANG
Keyword(s):  
Body Length ◽  
Present Model ◽  
The Body ◽  
Attraction Force ◽  
Bodies Of Revolution ◽  
Plane Flow ◽  
Lateral Forces ◽  
Close Proximity ◽  
Slender Bodies ◽  
Two Bodies

The irrotational flow past two slender bodies of revolution at angles of yaw, translating in parallel paths in very close proximity, is analysed by extending the classical slender body theory. The flow far away from the two bodies is shown to be a direct problem, which is represented in terms of two line sources along their longitudinal axes, at the strengths of the variation rates of their cross-section areas. The inner flow near the two bodies is reduced to the plane flow problem of the expanding (contracting) and lateral translations of two parallel circular cylinders with different radii, which is then solved analytically using conformal mapping. Consequently, an analytical flow solution has been obtained for two arbitrary slender bodies of revolution at angles of yaw translating in close proximity. The lateral forces and yaw moments acting on the two bodies are obtained in terms of integrals along the body lengths. A comparison is made among the present model for two slender bodies in close proximity, Tuck & Newman's (1974) model for two slender bodies far apart, and VSAERO (AMI)–commercial software based on potential flow theory and the boundary element method (BEM). The attraction force of the present model agrees well with the BEM result, when the clearance, h0, is within 20% of the body length, whereas the attraction force of Tuck & Newman is much smaller than the BEM result when h0 is within 30% of the body length, but approaches the latter when h0 is about half the body length. Numerical simulations are performed for the three typical manoeuvres of two bodies: (i) a body passing a stationary body, (ii) two bodies in a meeting manoeuvre (translating in opposite directions), and (iii) two bodies in a passing manoeuvre (translating in the same direction). The analysis reveals the orders of the lateral forces and yaw moments, as well as their variation trends in terms of the manoeuvre type, velocities, sizes, angles of yaw of the two bodies, and their proximity, etc. These irrotational dynamic features are expected to provide a basic understanding of this problem and will be beneficial to further numerical and experimental studies involving additional physical effects.

scholarly journals A numerical solution of axisymmetric cavity flows

1969 ◽  
Vol 37 (4) ◽  
pp. 671-688 ◽  
Author(s):  
Christopher Brennen
Keyword(s):  
Numerical Solution ◽  
Solid Wall ◽  
Cavity Flows ◽  
Viscous Effect ◽  
Cavitating Flows ◽  
Axisymmetric Cavity ◽  
Flow Choking ◽  
Series Of Experiments

In the first part of the paper a method is developed for the relaxation or numerical solution of axisymmetric fully cavitating flows. Employing the technique suggested in a paper by Woods (1951 a) of working in a transformed (ϕ ϕ)-plane, solutions are obtained for cavities behind a disk and a sphere in different sizes of solid wall tunnel. Under certain conditions flow ‘choking’ occurs.The results of a series of experiments carried out with such headforms are then reported. The apparent viscous effect on the position of separation from the sphere and thus on the drag proves to be of particular interest.

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