Injection of a heavy fluid into a light fluid in a closed-end pipe

2020 ◽  
Vol 32 (6) ◽  
pp. 063302 ◽  
Author(s):  
S. Akbari ◽  
S. M. Taghavi
Keyword(s):  
Heavy Fluid

scholarly journals An experimental investigation of convection in a fluid that exhibits phase change

1981 ◽  
Vol 102 ◽  
pp. 85-100 ◽  
Author(s):  
D. E. Fitzjarrald
Keyword(s):  
Thin Layer ◽  
Phase Change ◽  
Latent Heat ◽  
Thermal Gradient ◽  
Lower Boundary ◽  
Working Fluid ◽  
Heavy Fluid ◽  
Convective Motions ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard

Convection flows have been systematically observed in a layer of fluid between two isothermal horizontal boundaries. The working fluid was a nematic liquid crystal, which exhibits a liquid–liquid phase change at which latent heat is released and the density changed. In addition to ordinary Rayleigh–Bénard convection when either phase is present alone, there exist two distinct types of convective motions initiated by the unstable density difference. When a thin layer of heavy fluid is present near the top boundary, hexagons with downgoing centres exist with no imposed thermal gradient. When a thin layer of light fluid is brought on near the lower boundary, the hexagons have upshooting centres. In both cases, the motions are kept going once they are initiated by the instability due to release of latent heat. Relation of the results to applicable theories is discussed.

Forces Exerted on a Hovercraft by a Moving Pressure Distribution: Robustness of Mathematical Models

2006 ◽  
Vol 50 (01) ◽  
pp. 38-48 ◽  
Author(s):  
Gregory Zilman
Keyword(s):  
Free Surface ◽  
Mathematical Models ◽  
Pressure Distribution ◽  
Constant Pressure ◽  
Wave Resistance ◽  
Excess Pressure ◽  
Physical Parameters ◽  
Rectangular Region ◽  
Heavy Fluid ◽  
Side Force

The wave resistance, side force, and yawing moment acting on a hovercraft moving on the free surface of a heavy fluid is studied. The hovercraft is represented by a distributed excess pressure. Various types of pressure and bounding contours are considered. The sensitivity of the results to numerous uncertainties in the problem's physical parameters is investigated. It is found that constant pressure over a rectangular region moving with an angle of drift results in peculiar side force values. Several robust mathematical models of a moving hovercraft are proposed and analyzed.

Statistical characteristics of turbulent mixing in spherical and cylindrical converging Richtmyer–Meshkov instabilities

2021 ◽  
Vol 928 ◽  
Author(s):  
Xinliang Li ◽  
Yaowei Fu ◽  
Changping Yu ◽  
Li Li
Keyword(s):  
Turbulent Mixing ◽  
Initial Perturbation ◽  
Great Influence ◽  
Mixing Layers ◽  
Statistical Characteristics ◽  
Computational Domain ◽  
Heavy Fluid ◽  
Node Number ◽  
Geometric Effect ◽  
Atwood Number

In this paper, the Richtmyer–Meshkov instabilities in spherical and cylindrical converging geometries with a Mach number of approximately 1.5 are investigated by using the high resolution implicit large eddy simulation method, and the influence of the geometric effect on the turbulent mixing is investigated. The heavy fluid is sulphur hexafluoride (SF6), and the light fluid is nitrogen (N2). The shock wave converges from the heavy fluid into the light fluid. The Atwood number is 0.678. The total structured and uniform Cartesian grid node number in the main computational domain is 20483. In addition, to avoid the influence of boundary reflection, a sufficiently long sponge layer with 50 non-uniform coarse grids is added for each non-periodic boundary. Present numerical simulations have high and nonlinear initial perturbation levels, which rapidly lead to turbulent mixing in the mixing layers. Firstly, some physical-variable mean profiles, including mass fraction, Taylor Reynolds number, turbulent kinetic energy, enstrophy and helicity, are provided. Second, the mixing characteristics in the spherical and cylindrical turbulent mixing layers are investigated, such as molecular mixing fraction, efficiency Atwood number, turbulent mass-flux velocity and density self-correlation. Then, Reynolds stress and anisotropy are also investigated. Finally, the radial velocity, velocity divergence and enstrophy in the spherical and cylindrical turbulent mixing layers are studied using the method of conditional statistical analysis. Present numerical results show that the geometric effect has a great influence on the converging Richtmyer–Meshkov instability mixing layers.

Solitary stokes waves in heavy-fluid slit flow

1992 ◽  
Vol 26 (6) ◽  
pp. 935-937
Author(s):  
�. L. Amromin ◽  
V. A. Bushkovskii ◽  
D. Yu. Sadovnikov
Keyword(s):  
Heavy Fluid ◽  
Slit Flow ◽  
Stokes Waves
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