Super Accelerated Flow in Diverging Conical Pipes

2011 ◽  
Vol 110-116 ◽  
pp. 880-885
Author(s):  
G.J. Gutierrez ◽  
A. López Villa ◽  
A. Torres ◽  
S. Peralta ◽  
C. A. Vargas
Keyword(s):  
Free Surface ◽  
Free Fall ◽  
Liquid Column ◽  
Dimensional Model ◽  
One Dimensional ◽  
Low Viscosity ◽  
Accelerated Flow ◽  
Theoretical Results

The motion of the upper free surface of a liquid column released from rest in a vertical, conical container is analyzed theoretically and experimentally. An inviscid, one-dimensional model, for a slightly expanding pipe's radius, describes how the recently reported super free fall of liquids occurs in liquids of very low viscosity. Experiments agree with the theoretical results.

Layer formation in monodispersive suspensions and colloids

1996 ◽  
Vol 328 ◽  
pp. 297-311 ◽  
Author(s):  
A. E. Hosoi ◽  
Todd F. Dupont
Keyword(s):  
Burgers Equation ◽  
Fluid Motion ◽  
Layer Formation ◽  
Dimensional Model ◽  
Qualitative Comparison ◽  
Galerkin Approach ◽  
One Dimensional ◽  
Convection Roll ◽  
Lateral Temperature ◽  
Theoretical Results

We present theoretical results on spontaneous stratification of sedimenting suspensions and colloids caused by a lateral temperature gradient. Fluid motion is treated in the Stokes approximation, and motion of suspended particles is described by Burgers equation with convection. The internal structure and interaction of shocks at convection roll boundaries is studied numerically using a reduced one-dimensional model based on a Galerkin approach. Qualitative comparison is made to experimental data.

Combustion in Liquid-Fuel Rocket Motors

1959 ◽  
Vol 10 (1) ◽  
pp. 1-27 ◽  
Author(s):  
D. B. Spalding
Keyword(s):  
Droplet Size ◽  
Chemical Reaction ◽  
Liquid Fuel ◽  
Gas Temperature ◽  
Gas Velocity ◽  
Dimensional Model ◽  
Rocket Motors ◽  
One Dimensional ◽  
Theoretical Results ◽  
Propellant Rocket

SummaryThe paper provides a simplified picture of the processes occurring in liquid bi-propellant rocket motors. Droplet vaporisation, chemical reaction, and drag between gas and droplet are considered for a one-dimensional model. Quantitative theoretical results are presented for the variation of droplet size, droplet velocity, gas temperature and gas velocity within the chamber, particular attention being paid to the calculation of L*. The theory is applied to the German V2 rocket motor. Practical conclusions from, and extensions to, the theory are discussed.

ONE-DIMENSIONAL MODEL OF SOMITIC CELLS POLARIZATION IN A BISTABILITY WINDOW OF EMBRYONIC MESODERM

2009 ◽  
Vol 09 (03) ◽  
pp. 259-272 ◽  
Author(s):  
VALKO PETROV ◽  
JENS TIMMER
Keyword(s):  
Cell Polarization ◽  
Dynamical Process ◽  
Dimensional Model ◽  
Mechanical Tension ◽  
Bistable Behavior ◽  
One Dimensional ◽  
Posterior Direction ◽  
Somitic Mesoderm ◽  
Theoretical Results ◽  
Anterior Posterior

The considerations are based on the understanding that somitic cells polarization in bistability window of embryonic (pre-somitic) mesoderm is a dynamical process. It occurs in the form of a polarization wavefront of somite cells spread in anterior–posterior direction of the embryonic mesoderm. It is assumed that a macroscopic cell polarization has a bistable behavior corresponding to the molecular mechanism of bistability window formation. Moreover this type of polarization is supposed to be transmittable to the other cells by contact interaction. At the end, a volume of polarized cells is taken, which is able to create mechanical tension in the volume of nonpolarized neighbor cells and to inhibit their polarization. On this basis we explore the leading aspect of somitogenesis robustness by considering a simple wavefront model of polarization and analyzing its propagation in terms of the standard methods of qualitative theory of differential equations. The obtained theoretical results are interpreted in the context of their possible experimental verification.

Modelling Techniques in Applied Glaciology: Numerical Modelling of Avalanches

1983 ◽  
Vol 4 ◽  
pp. 297-297
Author(s):  
G. Brugnot
Keyword(s):  
Finite Difference Method ◽  
Transverse Velocity ◽  
Longitudinal Velocity ◽  
Momentum Conservation ◽  
Dimensional Model ◽  
One Dimensional ◽  
Modelling Techniques ◽  
Reference Grid ◽  
The One ◽  
Near Future

We consider the paper by Brugnot and Pochat (1981), which describes a one-dimensional model applied to a snow avalanche. The main advance made here is the introduction of the second dimension in the runout zone. Indeed, in the channelled course, we still use the one-dimensional model, but, when the avalanche spreads before stopping, we apply a (x, y) grid on the ground and six equations have to be solved: (1) for the avalanche body, one equation for continuity and two equations for momentum conservation, and (2) at the front, one equation for continuity and two equations for momentum conservation. We suppose the front to be a mobile jump, with longitudinal velocity varying more rapidly than transverse velocity.We solve these equations by a finite difference method. This involves many topological problems, due to the actual position of the front, which is defined by its intersection with the reference grid (SI, YJ). In the near future our two directions of research will be testing the code on actual avalanches and improving it by trying to make it cheaper without impairing its accuracy.

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.

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