scholarly journals Free-surface gravity flow due to a submerged body in uniform current

2019 ◽  
Vol 883 ◽  
Author(s):  
Y. A. Semenov ◽  
G. X. Wu
Keyword(s):  
Free Surface ◽  
Surface Gravity ◽  
Gravity Flow ◽  
Submerged Body ◽  
Uniform Current ◽  
Image Position

The Fundamental Solution in the Theory of Steady Motion of a Ship

1977 ◽  
Vol 21 (02) ◽  
pp. 82-88 ◽  
Author(s):  
F. Noblesse
Keyword(s):  
Free Surface ◽  
Green Function ◽  
Fundamental Solution ◽  
Velocity Potential ◽  
Steady Motion ◽  
Surface Gravity ◽  
Gravity Flow ◽  
The Green Function ◽  
Havelock Source ◽  
Uniform Stream

The paper presents a simplified new expression for the fundamental solution (the Green function) in the theory of steady motion of a ship, that is, the linearized disturbance velocity potential of the steady, inviscid free-surface gravity flow due to a unit source in an oncoming uniform stream, sometimes also referred to as the "Havelock source potential."

Two-dimensional free-surface gravity flow past blunt bodies

1972 ◽  
Vol 51 (3) ◽  
pp. 529-543 ◽  
Author(s):  
G. Dagan ◽  
M. P. Tulin
Keyword(s):  
Free Surface ◽  
Froude Number ◽  
The Body ◽  
Surface Gravity ◽  
Gravity Flow ◽  
Breaking Wave ◽  
Infinite Length ◽  
Two Dimensional ◽  
Flow Past ◽  
Outer Expansion

Most of the wave resistance of blunt bow displacement ships is caused by the bow-breaking wave. A theoretical study of the phenomenon for the two-dimensional steady flow past a blunt body of semi-infinite length is presented. The exact equations of free-surface gravity flow are solved approximately by two perturbation expansions. The small Froude number solution, representing the flow beneath an unbroken free surface before the body, is carried out to second order. The breaking of the free surface is assumed to be related to a local Taylor instability, and the application of the stability criterion determines the value of the critical Froude number which characterizes breaking. The high Froude number solution is based on the model of a jet detaching from the bow and not returning to the flow field. The outer expansion of the equations yields the linearized gravity flow equations, which are solved by the Wiener-Hopf technique. The inner expansion gives a nonlinear gravity-free flow in the vicinity of the bow a t zero order. The matching of the inner and outer expansions provides the jet thickness as well as the associated drag.

Nonlinear Aspects of Subcritical Shallow-Water Flow Past Two-Dimensional Obstructions

1978 ◽  
Vol 22 (04) ◽  
pp. 203-211
Author(s):  
Nils Salvesen ◽  
C. von Kerczek
Keyword(s):  
Free Surface ◽  
Shallow Water ◽  
Flow Problem ◽  
Free Stream ◽  
The Body ◽  
Two Dimensional ◽  
Third Order ◽  
Submerged Body ◽  
The Mean ◽  
The Waves

Some nonlinear aspects of the two-dimensional problem of a submerged body moving with constant speed in otherwise undisturbed water of uniform depth are considered. It is shown that a theory of Benjamin which predicts a uniform rise of the free surface ahead of the body and the lowering of the mean level of the waves behind it agrees well with experimental data. The local steady-flow problem is solved by a numerical method which satisfies the exact free-surface conditions. Third-order perturbation formulas for the downstream free waves are also presented. It is found that in sufficiently shallow water, the wavelength increases with increasing disturbance strength for fixed values of the free-stream-Froude number. This is opposite to the deepwater case where the wavelength decreases with increasing disturbance strength.

scholarly journals Calculation of the maximum velocity of gravity flow in the pond-clarifier with higher aquatic plants

2020 ◽  
Vol 168 ◽  
pp. 00061
Author(s):  
Yevhen Semenenko ◽  
Tetіana Demchenko ◽  
Artyom Pavlichenko
Keyword(s):  
Free Surface ◽  
Aquatic Plants ◽  
Fluid Velocity ◽  
Maximum Velocity ◽  
Resistance Coefficient ◽  
Gravity Flow ◽  
Recycled Water ◽  
Higher Aquatic Plants ◽  
Two Parameters ◽  
The Given

The analysis of the possible maximum fluid flow rates when using higher aquatic plants for clarification of recycled water in the pondclarifier of the tailing pond has carried out. The study has been performed on the basis of a mathematical model of a plane slow stationary gravity flow of a viscous fluid in two parallel layers. The results of the study made it possible to determine the fluid velocity through a layer of higher aquatic plants floating on a free surface. The maximum possible velocity depending on the layer porosity has been determined. This value is necessary to determine the rational parameters of the process of clarifying technical recycled water from particles of the given hydraulic size, taking into account the pond-clarifier geometric dimensions. It is shown that the velocity in the layer with higher aquatic plants has been determined by the ratio of two parameters of this layer - porosity and dimensionless resistance coefficient. It has been shown that the maximum velocity value coefficient in the layer with plants floating on free surface depends only on porosity of this layer and does not depend on its resistance coefficient.

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