scholarly journals First order perturbation approach for the free surface flow over a step with large Weber number

2021 ◽  
Vol 13 (2) ◽  
pp. 11-19
Author(s):  
May Manal BOUNIF ◽  
Abdelkader GASMI
Keyword(s):  
Free Surface ◽  
Weber Number ◽  
Perturbation Technique ◽  
Free Surface Flow ◽  
Approximate Solutions ◽  
Surface Flow ◽  
Perturbation Approach ◽  
Bernoulli’S Equation ◽  
Nonlinear Condition ◽  
Small Inclination

The problem of two-dimensional free surface flow of inviscid and incompressible fluid over a step is considered. The flow is assumed to be as steady and irrotational, the effect of the surface tension is considered, but the gravity force is neglected. This problem is characterized by the nonlinear condition given by Bernoulli's equation on the unknown free surface, which can be considered as part of the solution. The main purpose of this work is to give an approximate solution of this problem, by using the Hilbert transformation and the perturbation technique; the results are calculated for a large values of the Weber number and small inclination angle of the step values. These results demonstrate that the used method is easily implemented, and provides approximate solutions to these kinds of problems.

scholarly journals Developed liquid film passing a smoothed and wedge-shaped trailing edge: small-scale analysis and the ‘teapot effect’ at large Reynolds numbers

2021 ◽  
Vol 926 ◽  
Author(s):  
B. Scheichl ◽  
R.I. Bowles ◽  
G. Pasias
Keyword(s):  
Free Surface ◽  
Weber Number ◽  
Free Surface Flow ◽  
Reynolds Numbers ◽  
Surface Flow ◽  
Small Scale ◽  
Scale Analysis ◽  
Trailing Edge ◽  
Plate Edge ◽  
Wetting Properties

Recently, the authors considered a thin steady developed viscous free-surface flow passing the sharp trailing edge of a horizontally aligned flat plate under surface tension and the weak action of gravity, acting vertically, in the asymptotic slender-layer limit (J. Fluid Mech., vol. 850, 2018, pp. 924–953). We revisit the capillarity-driven short-scale viscous–inviscid interaction, on account of the inherent upstream influence, immediately downstream of the edge and scrutinise flow detachment on all smaller scales. We adhere to the assumption of a Froude number so large that choking at the plate edge is insignificant but envisage the variation of the relevant Weber number of $O(1)$ . The main focus, tackled essentially analytically, is the continuation of the structure of the flow towards scales much smaller than the interactive ones and where it no longer can be treated as slender. As a remarkable phenomenon, this analysis predicts harmonic capillary ripples of Rayleigh type, prevalent on the free surface upstream of the trailing edge. They exhibit an increase of both the wavelength and amplitude as the characteristic Weber number decreases. Finally, the theory clarifies the actual detachment process, within a rational description of flow separation. At this stage, the wetting properties of the fluid and the microscopically wedge-shaped edge, viewed as infinitely thin on the larger scales, come into play. As this geometry typically models the exit of a spout, the predicted wetting of the wedge is related to what in the literature is referred to as the teapot effect.

scholarly journals Laminar free-surface flow into a vertical cylinder

1975 ◽  
Vol 3 (1) ◽  
pp. 51-68 ◽  
Author(s):  
Thomas G. Smith ◽  
J.O. Wilkes
Keyword(s):  
Free Surface ◽  
Vertical Cylinder ◽  
Free Surface Flow ◽  
Surface Flow

Free-Surface Flow Simulations With Interactively Moving Bodies

2017 ◽  
Author(s):  
Arthur E. P. Veldman ◽  
Henk Seubers ◽  
Peter van der Plas ◽  
Joop Helder
Keyword(s):  
Free Surface ◽  
Free Fall ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Numerical Solution Method ◽  
Flow Simulations ◽  
Floating Object ◽  
Offshore Industry ◽  
Floating Objects ◽  
Moving Bodies

The simulation of free-surface flow around moored or floating objects faces a series of challenges, concerning the flow modelling and the numerical solution method. One of the challenges is the simulation of objects whose dynamics is determined by a two-way interaction with the incoming waves. The ‘traditional’ way of numerically coupling the flow dynamics with the dynamics of a floating object becomes unstable (or requires severe underrelaxation) when the added mass is larger than the mass of the object. To deal with this two-way interaction, a more simultaneous type of numerical coupling is being developed. The paper will focus on this issue. To demonstrate the quasi-simultaneous method, a number of simulation results for engineering applications from the offshore industry will be presented, such as the motion of a moored TLP platform in extreme waves, and a free-fall life boat dropping into wavy water.

Model coupling techniques for free-surface flow problems: Part II

2005 ◽  
Vol 63 (5-7) ◽  
pp. e1897-e1908 ◽  
Author(s):  
E. Miglio ◽  
S. Perotto ◽  
F. Saleri
Keyword(s):  
Free Surface ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Model Coupling ◽  
Flow Problems ◽  
Coupling Techniques
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