scholarly journals Unsteady Fluid Motion Between Two Infinite Walls Under Variable Body Force

Author(s):  
Rostislav Lemdiasov ◽  
Valeriy Tenishev ◽  
Alexander Fedoseyev
Author(s):  
Alexander A. Papin ◽  
Margarita A. Tokareva ◽  
Rudolf A. Virts

The solvability of the initial-boundary value problem is proved for the system of equations of one-dimensional unsteady fluid motion in a heat-conducting viscous porous medium


2002 ◽  
Vol 14 (7) ◽  
pp. 2572 ◽  
Author(s):  
R. A. Lemdiasov ◽  
V. M. Tenishev ◽  
A. I. Fedoseyev

2019 ◽  
pp. 79-86
Author(s):  
M. Ya. Khabibullin ◽  
I. G. Arslanov ◽  
R. I. Suleymanov

To study the unsteady fluid motion in a tubing string, when it is pumped, the classical equation of hydraulic impact is solved at the first stage. The solution was carried out by separating the variables taking into account all real initial and boundary conditions. The problem of distributing the hydraulic impact of a viscous liquid in a tubing string from the operation of impulse devices at the bottom of a well as a homogeneous system in which all processes occurring during fluid injection are interrelated. As a result, expressions were obtained for determining the velocity of the fluid and the amplitude of the change in the fluid pressure in any arbitrary section of the liquid column inside the tubing string, over which graphical dependencies are plotted in relative values for different pipe diameters. The results obtained make it possible to predict the reliability of the pipe string for pulsed non-stationary injection of liquid under pressure.


Materials ◽  
2005 ◽  
Author(s):  
A. Shooshtari ◽  
S. Chowdhury ◽  
M. Ohadi

In recent decades, the phenomenon of electrohydrodynamics (EHD) has gained prominence due to its potential applications in microsystems. One such application is pumping and transport of dielectric fluids in micropumps meant for cooling or other such purposes. Electrohydrodynamics can be defined as a direct coupling between the electric and hydrodynamic fields, where the electric field produces fluid motion. The motion of the fluid can occur due to an electrical body force being exerted on the fluid. In single-phase liquid flows, the electrophoretic (Coulombic) component of the electrical body force is the main driving force that acts on the free charge carriers. There are different physico-chemical processes that result in production of free charge carriers inside fluids; among these processes, the ion-injection and conduction/dissociation of ionic pairs are typical and hence worth mentioning. So far, several different numerical methods have been developed to model the EHD pumping effect due to the ion-injection process and the process of dissociation of ionic pairs. This paper presents a numerical model of the electrophoretic force in dielectric liquids that combines both the aspects of dissociation of ionic pairs and ion-injection processes. In this modeling, it is assumed that the ion injection process is unipolar. However, the dissociation process generates both positive and negative ions. Therefore, modeling of this process involves determining the concentration of both types of ions. The present modeling procedure is used to simulate a mesoscale electrohydrodynamic pump where the numerical and experimental results are compared and found to be in agreement within acceptable limits. This modeling technique serves as an effective tool for prediction and optimization of the electrohydrodynamic pumps.


1988 ◽  
Vol 110 (3) ◽  
pp. 590-595 ◽  
Author(s):  
K. N. Lakshmisha ◽  
S. Venkateswaran ◽  
G. Nath

A numerical solution of the unsteady boundary layer equations under similarity assumptions is obtained. The solution represents the three-dimensional unsteady fluid motion caused by the time-dependent stretching of a flat boundary. It has been shown that a self-similar solution exists when either the rate of stretching is decreasing with time or it is constant. Three different numerical techniques are applied and a comparison is made among them as well as with earlier results. Analysis is made for various situations like deceleration in stretching of the boundary, mass transfer at the surface, saddle and nodal point flows, and the effect of a magnetic field. Both the constant temperature and constant heat flux conditions at the wall have been studied.


Author(s):  
Yu. P. Morozov

Based on the solution of the problem of non-stationary heat transfer during fluid motion in underground permeable layers, dependence was obtained to determine the operating time of the geothermal circulation system in the regime of constant and falling temperatures. It has been established that for a thickness of the layer H <4 m, the influence of heat influxes at = 0.99 and = 0.5 is practically the same, but for a thickness of the layer H> 5 m, the influence of heat inflows depends significantly on temperature. At a thickness of the permeable formation H> 20 m, the heat transfer at = 0.99 has virtually no effect on the thermal processes in the permeable formation, but at = 0.5 the heat influx, depending on the speed of movement, can be from 50 to 90%. Only at H> 50 m, the effect of heat influx significantly decreases and amounts, depending on the filtration rate, from 50 to 10%. The thermal effect of the rock mass with its thickness of more than 10 m, the distance between the discharge circuit and operation, as well as the speed of the coolant have almost no effect on the determination of the operating time of the GCS in constant temperature mode. During operation of the GCS at a dimensionless coolant temperature = 0.5, the velocity of the coolant is significant. With an increase in the speed of the coolant in two times, the error changes by 1.5 times.


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