Oscillatory Rayleigh-Marangoni convection in a layer heated from above: Numerical simulations with an undeformable free surface

2003 ◽  
Vol 67 (2) ◽  
Author(s):  
Thomas Boeck ◽  
Matthias Jurgk ◽  
Ute Bahr
Keyword(s):  
Free Surface ◽  
Numerical Simulations ◽  
Marangoni Convection

Evaluation of Marangoni convection and free surface velocity of molten tungsten for tungsten divertor

2019 ◽  
Vol 140 ◽  
pp. 117-122 ◽  
Author(s):  
Kohei Hamaguchi ◽  
Eiji Hoashi ◽  
Takafumi Okita ◽  
Kenzo Ibano ◽  
Yoshio Ueda
Keyword(s):  
Free Surface ◽  
Marangoni Convection ◽  
Surface Velocity ◽  
Free Surface Velocity

scholarly journals The oscillatory longwave Marangoni convection in a thin film heated from below

2021 ◽  
Vol 3 (10) ◽  
Author(s):  
Anna Samoilova ◽  
Alexander Nepomnyashchy
Keyword(s):  
Thin Film ◽  
Free Surface ◽  
Large Scale ◽  
Marangoni Convection ◽  
Thin Liquid Film ◽  
Stationary Regime ◽  
Oscillatory Regime ◽  
Oscillatory Flows ◽  
The Past ◽  
Heating From Below

Abstract A novel type of Marangoni convection was predicted theoretically a decade ago. The thin liquid film atop a substrate of low thermal conductivity was considered. In the case of heating from below, the Marangoni convection emerges not only in a conventional stationary regime, but also as oscillatory flows. Specifically, the oscillatory Marangoni convection emerges if (1) the heat flux from the free surface is small, and (2) the large-scale deformation of the free surface is allowed. During the past decade, this novel Marangoni convection was detected and investigated in several other theoretical works. The review discusses the recent achievements in studying the oscillatory Marangoni convection in a thin film heated from below. The guiding data for observation of the oscillatory regime are also provided.

Interaction of surface waves with turbulence: direct numerical simulations of turbulent open-channel flow

1995 ◽  
Vol 286 ◽  
pp. 1-23 ◽  
Author(s):  
Vadim Borue ◽  
Steven A. Orszag ◽  
Ilya Staroselsky
Keyword(s):  
Free Surface ◽  
Numerical Simulations ◽  
Channel Flow ◽  
Gravity Waves ◽  
Open Channel ◽  
Open Channel Flow ◽  
Surface Region ◽  
Direct Numerical Simulations ◽  
Turbulence Production ◽  
Wind Sea

We report direct numerical simulations of incompressible unsteady open-channel flow. Two mechanisms of turbulence production are considered: shear at the bottom and externally imposed stress at the free surface. We concentrate upon the effects of mutual interaction of small-amplitude gravity waves with in-depth turbulence and statistical properties of the near-free-surface region. Extensions of our approach can be used to study turbulent mixing in the upper ocean and wind–sea interaction, and to provide diagnostics of bulk turbulence.

Numerical Simulations of Ship Bow and Shoulder Wave Breaking in Different Advancing Speeds

2018 ◽  
Author(s):  
Zhen Ren ◽  
Jianhua Wang ◽  
Decheng Wan
Keyword(s):  
Free Surface ◽  
Numerical Simulations ◽  
Wave Breaking ◽  
Wave Pattern ◽  
Breaking Wave ◽  
Wake Field ◽  
Bow Wave ◽  
Calm Water ◽  
Wave Phenomena ◽  
Good Agreement

The KCS model is employed for the numerical simulations to investigate the wave breaking phenomena of the bow and shoulder wave. RANS approach coupled with high resolution VOF technique is used to resolve the free surface. In order to study the speed effects on the phenomena of ship wave breaking, four different speeds, i.e. Fr = 0.26, 0.30, 0.32, 0.35, are investigated in calm water. Predicted resistance and wave patterns under Fr = 0.26 are validated with the available experiment data, and good agreement is achieved. For the Fr = 0.26 case, the wave pattern is steady, and the alternate variation of vorticity appear near the free surface is associated with the wake field. The breaking wave phenomena can be observed when the Froude number is over 0.32 and the Fr = 0.35 case shows most violent breaking bow wave. For the Fr = 0.35 case, the process of overturning and breaking of bow wave is observed clearly, and at the tail of bow wave, some breaking features of free surface are also captured. The reconnection of the initial plunger with the free surface results in a pair of counter-rotating vortex that is responsible for the second plunger and scar.

Numerical Simulations of Highly Nonlinear Steady and Unsteady Free Surface Flows

2011 ◽  
Vol 23 (6) ◽  
pp. 683-696 ◽  
Author(s):  
Chi Yang ◽  
Fuxin Huang ◽  
Lijue Wang ◽  
De-cheng Wan
Keyword(s):  
Free Surface ◽  
Numerical Simulations ◽  
Free Surface Flows ◽  
Surface Flows ◽  
Highly Nonlinear

Numerical Simulation of Free-Surface Turbulence

1994 ◽  
Vol 47 (6S) ◽  
pp. S163-S165
Author(s):  
Douglas G. Dommermuth ◽  
Rebecca C. Y. Mui
Keyword(s):  
Numerical Simulation ◽  
Numerical Modeling ◽  
Free Surface ◽  
Numerical Simulations ◽  
Free Surface Flows ◽  
Direct Numerical Simulations ◽  
Large Eddy Simulations ◽  
Surface Flows ◽  
Large Eddy ◽  
Free Surface Turbulence

Direct numerical simulations and large-eddy simulations of turbulent free-surface flows are currently being performed to investigate the roughening of the surface, and the scattering, radiation, and dissipation of waves by turbulence. The numerical simulation of turbulent free-surface flows is briefly reviewed. The numerical, modeling, and hardware issues are discussed.

Numerical simulations of nonlinear axisymmetric flows with a free surface

1987 ◽  
Vol 178 ◽  
pp. 195-219 ◽  
Author(s):  
Douglas G. Dommermuth ◽  
Dick K. P. Yue
Keyword(s):  
Free Surface ◽  
Numerical Simulations ◽  
Three Dimensional ◽  
Vertical Cylinder ◽  
Free Surface Flows ◽  
Boundary Integral ◽  
The Body ◽  
Special Treatment ◽  
Computational Domain ◽  
Vortex Sheets

A numerical method is developed for nonlinear three-dimensional but axisymmetric free-surface problems using a mixed Eulerian-Lagrangian scheme under the assumption of potential flow. Taking advantage of axisymmetry, Rankine ring sources are used in a Green's theorem boundary-integral formulation to solve the field equation; and the free surface is then updated in time following Lagrangian points. A special treatment of the free surface and body intersection points is generalized to this case which avoids the difficulties associated with the singularity there. To allow for long-time simulations, the nonlinear computational domain is matched to a transient linear wavefield outside. When the matching boundary is placed at a suitable distance (depending on wave amplitude), numerical simulations can, in principle, be continued indefinitely in time. Based on a simple stability argument, a regriding algorithm similar to that of Fink & Soh (1974) for vortex sheets is generalized to free-surface flows, which removes the instabilities experienced by earlier investigators and eliminates the need for artificial smoothing. The resulting scheme is very robust and stable.For illustration, three computational examples are presented: (i) the growth and collapse of a vapour cavity near the free surface; (ii) the heaving of a floating vertical cylinder starting from rest; and (iii) the heaving of an inverted vertical cone. For the cavity problem, there is excellent agreement with available experiments. For the wave-body interaction calculations, we are able to obtain and analyse steady-state (limit-cycle) results for the force and flow field in the vicinity of the body.

scholarly journals Early-time free-surface flow driven by a deforming boundary

2015 ◽  
Vol 767 ◽  
pp. 811-841 ◽  
Author(s):  
C. Frederik Brasz ◽  
Craig B. Arnold ◽  
Howard A. Stone ◽  
John R. Lister
Keyword(s):  
Free Surface ◽  
Numerical Simulations ◽  
Liquid Layer ◽  
Early Time ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Solid Boundary ◽  
Jet Formation ◽  
Domain Perturbation ◽  
Quiescent Liquid

AbstractWhen a solid boundary deforms rapidly into a quiescent liquid layer, a flow is induced that can lead to jet formation. An asymptotic analytical solution is presented for this flow, driven by a solid boundary deforming with dimensionless vertical velocity $V_{b}(x,t)={\it\epsilon}(1+\cos x)\,f(t)$, where the amplitude ${\it\epsilon}$ is small relative to the wavelength and the time dependence $f(t)$ approaches 0 for large $t$. Initially, the flow is directed outwards from the crest of the deformation and slows with the slowing of the boundary motion. A domain-perturbation method is used to reveal that, when the boundary stops moving, nonlinear interactions with the free surface leave a remnant momentum directed back towards the crest, and this momentum can be a precursor to jet formation. This scenario arises in a laser-induced printing technique in which an expanding blister imparts momentum into a liquid film to form a jet. The analysis provides insight into the physics underlying the interaction between the deforming boundary and free surface, in particular, the dependence of the remnant flow on the thickness of the liquid layer and the deformation amplitude and wavelength. Numerical simulations are used to show the range of validity of the analytical results, and the domain-perturbation solution is extended to an axisymmetric domain with a Gaussian boundary deformation to compare with previous numerical simulations of blister-actuated laser-induced forward transfer.

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