scholarly journals CALCULATION OF THERMODYNAMIC CHARACTERISTICSOF THE ASCENDING SWIRLING FLOW WITH FIVE SOURCES OF HEATING

2017 ◽  
pp. 100-106
Author(s):  
D. D. Barannikova ◽  
A. G. Obukhov
Keyword(s):  
Stokes Equations ◽  
Swirling Flow ◽  
Complete System ◽  
Thermodynamic Characteristics ◽  
Navier Stokes ◽  
Gas Flows ◽  
Explicit Difference Scheme ◽  
Local Pressure ◽  
Navier Stokes Equations ◽  
Constant Coefficients

Calculations of the thermodynamic characteristics of air flows were carried out when several local sources were heated by the underlying surface. The basic mathematical model is the complete system of Navier-Stokes equations with constant coefficients of viscosity and thermal conductivity when gravity and Coriolis are taken into account. Numerical experiments were carried out using an explicit difference scheme with an appropriate choice of the initial and boundary conditions. The varying local pressure differences found during the calculations lead to the corresponding gas flows both in horizontal and vertical planes.

scholarly journals THREE-DIMENSIONAL INSTANTANEOUS STREAMLINESOF GAS FLOWS FOR SIMULATION THE STEADY-STATE OUTPUT OF AN ARTIFICIAL TORNADO

2018 ◽  
pp. 71-76
Author(s):  
R. E. Volkov ◽  
A. G. Obukhov
Keyword(s):  
Steady State ◽  
Stokes Equations ◽  
Complete System ◽  
Three Dimensional ◽  
Unsteady Flows ◽  
Navier Stokes ◽  
Gas Flows ◽  
Heat Conducting ◽  
Navier Stokes Equations ◽  
Coriolis Forces

The method of parallelizing a numerical solution of the complete system of Navier - Stokes equations is used to describe three-dimensional unsteady flows of a viscous compressible heat-conducting gas in ascending swirling flows. In this case the action of gravity and Coriolis forces is taken into account, and the coefficients of viscosity and thermal conductivity are assumed to be constant. The results of the numerical construction of instantaneous streamlines characterizing complex three-dimensional flows are presented for simulation the steady-state output of an ascend-ing swirling air flow in an artificial tornado.

scholarly journals PARALLEL COMPUTATIONS IN STUDIES OF DEPENDENCE OF GAS DYNAMIC PARAMETERS OF UPWARD SWIRLING FLOW OF GAS ON BLOWING VELOCITY

2016 ◽  
pp. 92-97
Author(s):  
R. E. Volkov ◽  
A. G. Obukhov
Keyword(s):  
Stokes Equations ◽  
Swirling Flow ◽  
Initial Conditions ◽  
Exact Analytical Solution ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Heat Conducting ◽  
Computational Domain ◽  
Navier Stokes Equations ◽  
Gas Dynamic

The rectangular parallelepiped explicit difference schemes for the numerical solution of the complete built system of Navier-Stokes equations. These solutions describe the three-dimensional flow of a compressible viscous heat-conducting gas in a rising swirling flows, provided the forces of gravity and Coriolis. This assumes constancy of the coefficient of viscosity and thermal conductivity. The initial conditions are the features that are the exact analytical solution of the complete Navier-Stokes equations. Propose specific boundary conditions under which the upward flow of gas is modeled by blowing through the square hole in the upper surface of the computational domain. A variant of parallelization algorithm for calculating gas dynamic and energy characteristics. The results of calculations of gasdynamic parameters dependency on the speed of the vertical blowing by the time the flow of a steady state flow.

scholarly journals FIRST PROJECTION OF THE EQUATION OF MOTION IN THE CYLINDRICAL COORDINATE SYSTEM

2016 ◽  
pp. 90-92
Author(s):  
A. G. Obukhov ◽  
R. E. Volkov
Keyword(s):  
Coordinate System ◽  
Stokes Equations ◽  
Equation Of Motion ◽  
Cylindrical Coordinate System ◽  
Navier Stokes ◽  
Gas Flows ◽  
Heat Conducting ◽  
Complex Flows ◽  
Navier Stokes Equations ◽  
Cylindrical Coordinate

It is proved that complex flows of the viscous compressible heat-conducting gas, arising during heating the vertical field, have a pronounced axial symmetry. Therefore, for the numerical solution of the full Navier-Stokes equations for description of such gas flows it are advisable to use a cylindrical coordinate system. This paper describes the transformation of the first projection of the equation of motion of the full Navier-Stokes equations system. The result of the transformation is a record of the first projection of the equation of a continuous medium motion in the cylindrical coordinate system.

scholarly journals NUMERICAL CALCULATION OF CONVECTIVE FLOW OF GAS AT CIRCULAR-TYPE SCHEME OF HEATING

2015 ◽  
pp. 87-93
Author(s):  
E. M. Sorokina ◽  
A. G. Obukhov
Keyword(s):  
Convective Flow ◽  
Stokes Equations ◽  
Complete System ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Heat Conducting ◽  
Boundary Condi Tions ◽  
Navier Stokes Equations ◽  
Viscous Heat ◽  
Condi Tions

To investigate the convective flows of polytropic gas a complete system of Navier - Stokes equations is consid-ered. As the initial and boundary conditions the specific ratios are offered. The proposed initial and boundary condi-tions realization is carried out at construction of the numerical solution of the complete system of Navier - Stokes equations for modeling the unsteady state three-dimensional convection flows of the compressible viscous heat-conducting gas in the isolated cubic area. Three components of the velocity vector are calculated for the initial stage of the convective flow. It is shown that the velocity components are complex and depend essentially on the heating shape, height and time.

scholarly journals METHOD OF PARALLELIZATION OF NUMERICAL ALGORITHMOF NAVIER-STOKES EQUATIONS COMPLETE SYSTEM

2016 ◽  
pp. 92-98
Author(s):  
R. E. Volkov ◽  
A. G. Obukhov
Keyword(s):  
Thermal Conductivity ◽  
Gas Flow ◽  
Stokes Equations ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Computation Time ◽  
Navier Stokes ◽  
Heat Conducting ◽  
Navier Stokes Equations ◽  
Comparison Of The Results

The article considers the features of numerical construction of solutions of the Navier-Stokes equations full system describing a three-dimensional flow of compressible viscous heat-conducting gas under the action of gravity and Coriolis forces. It is shown that accounting of dissipative properties of viscosity and thermal conductivity of the moving continuum, even with constant coefficients of viscosity and thermal conductivity, as well as the use of explicit difference scheme calculation imposes significant restrictions on numerical experiments aimed at studying the arising complex flows of gas or liquid. First of all, it is associated with a signifi- cant complication of the system of equations, the restrictions on the value of the calculated steps in space and time, increasing the total computation time. One of the options is proposed of algorithm parallelization of numerical solution of the complete Navier - Stokes equations system in the vertical spatial coordinate. This parallelization option can significantly increase the computing performance and reduce the overall time of counting. A comparison of the results of calculation of one of options of gas flow in the upward swirling flow obtained by serial and parallel programs is presented.

Velocity Characteristics of Confined Coaxial Jets With and Without Swirl

1980 ◽  
Vol 102 (1) ◽  
pp. 47-53 ◽  
Author(s):  
M. A. Habib ◽  
J. H. Whitelaw
Keyword(s):  
Stokes Equations ◽  
Swirling Flow ◽  
Laser Doppler Anemometry ◽  
Velocity Ratio ◽  
Equation Model ◽  
Navier Stokes ◽  
Recirculation Region ◽  
Jet Flows ◽  
Mean Velocity ◽  
Navier Stokes Equations

Measured values of the velocity characteristics of turbulent, confined, coaxial-jet flows have been obtained, without swirl, for ratios of maximum annulus to pipe velocities of 1.0 and 3.0 and with a swirl number of 0.23 for a velocity ratio of 3.0. They were obtained by a combination of pressure probes, hot-wire and laser-Doppler anemometry. The results are compared with calculations, based on the solution of finite-difference forms of the steady, Navier-Stokes equations, and an effective-viscosity hypothesis. The measurements allow the influence of confinement and swirl to be quantified and show, for example, the increased tendency towards centerline recirculation which results from both. The results with the three types of instrumentation allow a comparison within the corner recirculation region which reveals that serious errors of interpretation of mean-velocity measurements need not arise. The two-equation model, although able to represent the non-swirling flow is less appropriate to the swirling flow and the reasons are indicated.

A CFD Model for Real Gas Flows

2000 ◽  
Author(s):  
Carlo Cravero ◽  
Antonio Satta
Keyword(s):  
Numerical Solutions ◽  
Turbulence Modeling ◽  
Stokes Equations ◽  
Fluid Model ◽  
Industrial Applications ◽  
Navier Stokes ◽  
Gas Flows ◽  
Navier Stokes Equations ◽  
Real Fluid ◽  
Solution Methods

Numerical solutions of Navier-Stokes equations are nowadays widely used for several industrial applications in different fields (aerodynamic, propulsion, naval, combustion, etc..), but the solution methods still require significant improvements especially in two aspects: turbulence modeling and fluid modeling. The paper describes in some detail a real fluid model based on Redlich-Kwong-Aungier equation of state and its implementation into a Navier-Stokes solver developed by the authors for turbomachinery flows analysis.

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