A numerical study has been conducted on the internal pressure distribution of a ventilated supercavity generated from a backward facing cavitator under different air entrainment coefficients, Froude numbers, and blockage ratios. An Eulerian multiphase model with a free surface model is employed and validated by the experiments conducted at St. Anthony Falls Laboratory of the University of Minnesota. The results show that the internal pressure in the major portion of the supercavity is primarily governed by the hydrostatic pressure of water, while a steep adverse pressure gradient occurs at the closure region. Increasing the air entrainment coefficient does not largely change the pressure distribution, while the cavity tail extends longer and consequently the pressure gradient near the closure decreases. At smaller Froude number, there is a more pronounced gravitational effect on the supercavity with increasing uplift of the lower surface of the cavity and a decreasing uniformity of the pressure distribution in the supercavity. With the increase of blockage ratio, the overall pressure within the supercavity decreases as well as the pressure gradient in the main portion of the supercavity. The current study shows that the assumption of uniform pressure distribution in ventilated supercavities is not always valid, especially at low Fr. However, an alternative definition of cavitation number in such cases remains to be defined and experimentally ascertained in future investigations.

References

1.
Nesteruk
,
I.
,
2012
,
Supercavitation
,
Springer-Verlag
,
Berlin
.
2.
Wosnik
,
M.
,
Schauer
,
T. J.
, and
Arndt
,
R. E. A.
,
2003
, “
Experimental Study of a Ventilated Supercavitating Vehicle
,”
Fifth International Symposium on Cavitation
, Osaka, Japan, Paper No. Cav03-OS-7-008.
3.
Xiang
,
M.
,
Cheung
,
S. C. P.
,
Tu
,
J. Y.
, and
Zhang
,
W. H.
,
2011
, “
Numerical Research on Drag Reduction by Ventilated Partial Cavity Based on Two-Fluid Model
,”
Ocean Eng.
,
38
(
17
), pp.
2023
2032
.
4.
Nesteruk
,
I.
,
2014
, “
Shape of Slender Axisymmetric Ventilated Supercavities
,”
J. Comput. Eng.
,
2014
, p.
501590
.
5.
Kawakami
,
E.
, and
Arndt
,
R. E. A.
,
2011
, “
Investigation of the Behavior of Ventilated Supercavities
,”
ASME J. Fluids Eng.
,
133
(
9
), p.
091305
.
6.
Lee
,
S. J.
,
Kawakami
,
E.
, and
Arndt
,
R. E. A.
,
2013
, “
Investigation of the Behavior of Ventilated Supercavities in a Periodic Gust Flow
,”
ASME J. Fluids Eng.
,
135
(
8
), p.
081301
.
7.
Karn
,
A.
,
Arndt
,
R. E. A.
, and
Hong
,
J.
,
2016
, “
An Experimental Investigation Into Supercavity Closure Mechanisms
,”
J. Fluid Mech.
,
789
, pp.
259
284
.
8.
Karn
,
A.
,
Arndt
,
R. E. A.
, and
Hong
,
J.
,
2015
, “
Dependence of Supercavity Closure Upon Flow Unsteadiness
,”
Exp. Therm. Fluid Sci.
,
68
, pp.
493
498
.
9.
Pan
,
Z.
,
Lu
,
C.
,
Chen
,
Y.
, and
Hu
,
S.
,
2010
, “
Numerical Study of Periodically Forced-Pitching of a Supercavitating Vehicle
,”
J. Hydrodyn.
,
22
(
5
), pp.
899
904
.
10.
Hu
,
X.
, and
Xiong
,
Y.
,
2013
, “
Numerical Simulation on Ventilated Cavity Flow With Different Turbulence Models
,”
Appl. Mech. Mater.
,
368–370
, pp.
544
548
.
11.
Rashidi
,
I.
,
Pasandideh-Fard
,
M.
,
Passandideh-Fard
,
M.
, and
Nouri
,
N. M.
,
2014
, “
Numerical and Experimental Study of a Ventilated Supercavitating Vehicle
,”
ASME J. Fluids Eng.
,
136
(
10
), p.
101301
.
12.
Zhou
,
J.
,
Yu
,
K.
,
Min
,
J.
, and
Yang
,
M.
,
2010
, “
The Comparative Study of Ventilated Super Cavity Shape in Water Tunnel and Infinite Flow Field
,”
J. Hydrodyn.
,
22
(
5
), pp.
689
696
.
13.
Karn
,
A.
,
Monson
,
G.
,
Ellis
,
C.
,
Hong
,
J.
,
Arndt
,
R. E. A.
, and
Gulliver
,
J.
,
2015
, “
Mass Transfer Studies Across Ventilated Hydrofoils: A Step Towards Hydroturbine Aeration
,”
Int. J. Heat Mass Transfer
,
87
, pp.
512
520
.
14.
Barth
,
T. J.
, and
Jespersen
,
D. C.
,
1989
, “
The Design and Application of Upwind Schemes on Unstructured Meshes
,”
27th AIAA Aerospace Sciences Meeting
, Reno, NV, Jan. 9–12,
AIAA
Paper No. 89-0366.
15.
Zwart
,
P. J.
,
Scheuerer
,
M.
, and
Bogner
,
M.
,
2005
, “
Numerical Modelling of Free Surface and Cavitating Flows
,”
VKI Lecture Series: Industrial Two-Phase Flow CFD
, Brussels, Belgium, pp.
1
25
.
16.
Zwart
,
P. J.
,
Godin
,
P. G.
,
Penrose
,
J.
, and
Rhee
,
S. H.
,
2008
, “
Simulation of Unsteady Free-Surface Flow Around a Ship Hull Using a Fully Coupled Multi-Phase Flow Method
,”
J. Mar. Sci. Technol.
,
13
(
4
), pp.
346
355
.
17.
Brennen
,
C.
,
1969
, “
A Numerical Solution of Axisymmetric Cavity Flows
,”
J. Fluid Mech.
,
37
(
4
), pp.
671
688
.
18.
Karn
,
A.
,
Arndt
,
R. E. A.
, and
Hong
,
J.
,
2016
, “
Gas Entrainment Behaviors in the Formation and Collapse of a Ventilated Supercavity
,”
Exp. Therm. Fluid Sci.
,
79
, pp. 294–300.
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