scholarly journals Numerical Analysis of Multi-Phase Flow around Supercavitating Body at Various Cavitator Angle of Attack and Ventilation Mass Flux

2020 ◽  
Vol 10 (12) ◽  
pp. 4228
Author(s):  
Dong-Hyun Kim ◽  
SalaiSargunan S Paramanantham ◽  
Warn-Gyu Park
Keyword(s):  
Flow Analysis ◽  
Angle Of Attack ◽  
Homogeneous Mixture ◽  
Navier Stokes ◽  
Cavitation Flow ◽  
Navier Stokes Equation ◽  
Gas Phases ◽  
Continuity Equations ◽  
Mixture Phase ◽  
Multi Phase Flow

Cavitation flow is an important issue in many areas of mechanical engineering. In this study, the natural and ventilated cavitation analyses were performed using the developed code for the cavitation flow analysis. The governing equation is the Navier-Stokes equation based on a homogeneous mixture model. This model assumes that all fluids are in an equilibrium state of momentum. The momentum equations are solved using the homogeneous mixture phase, although the continuity equations are solved in the liquid, vapor, and gas phases, separately. Computational analysis was performed for the different injection conditions and inflow velocity conditions under the same conditions as the experiments. The comparison between the cavitation shape and the drag showed good agreement with the experiments. Based on this, this study predicted the change of cavitation shape according to the change of cavitator angle of attack.

scholarly journals SELF-SIMILAR ANALYTIC SOLUTION OF THE TWO-DIMENSIONAL NAVIER-STOKES EQUATION WITH A NON-NEWTONIAN TYPE OF VISCOSITY

2016 ◽  
Vol 21 (1) ◽  
pp. 83-94 ◽  
Author(s):  
Imre Ferenc Barna ◽  
Gabriella Bognar ◽  
Krisztian Hriczo
Keyword(s):  
Trial Function ◽  
Analytic Solution ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Newtonian Viscosity ◽  
Navier Stokes Equation ◽  
Continuity Equations ◽  
Eulerian Description ◽  
Self Similar ◽  
Newtonian Type

We investigate Navier-Stokes (NS) and the continuity equations in Cartesian coordinates and Eulerian description for the two dimensional incompressible nonNewtonian fluids. Due to the non-Newtonian viscosity we consider the Ladyzenskaya model with a non-linear velocity dependent stress tensor. The key idea is the multidimensional generalization of the well-known self-similar Ansatz, which has already been used for non-compressible and compressible viscous flow studies. Geometrical interpretations of the trial function are also discussed. Our recent results are compared to the former Newtonian ones.

scholarly journals Numerical study of flow across an ellipse and a circle placed in a uniform stream of infinite extent

2020 ◽  
Author(s):  
Adnan Anwar ◽  
Mudassar Razzaq ◽  
Liudmila Rivkind
Keyword(s):  
Reynolds Number ◽  
Numerical Study ◽  
Angle Of Attack ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Reynolds Number Flow ◽  
Infinite Extent ◽  
Number Flow ◽  
Conforming Finite Element Method ◽  
Drag And Lift

As an example of an aerodynamics prototypical study, we examined a two-dimensional low Reynolds number flow over obstacles immersed in a stream of infinite extent. The Navier Stokes equation is being discretized by non conforming finite element method approach. The resulting discretized nonlinear algebraic system is being solved by using the fixpoint method and the Newton method and multigrid method for the linear sub-problem employed. The magnitude of the uniform upstream velocity under the study of the problem for Reynolds number in the range 1 < Re < 100 and the angle of attack of the upstream velocity at α = -5; 0; 5 degrees performed. Analysis of the resulting drag and lift forces acting on obstacles with respect to the angle of attack of the upstream velocity and the Reynolds number is made. Moreover, the influence of one obstacle on the resulting drag and lift coefficients of other obstacles determined. The results are being presented in a graphical and vector form.

scholarly journals A MAGNETOHYDRODYNAMIC STUDY OF BEHAVIOR IN AN ELECTROLYTE FLUID USING NUMERICAL AND EXPERIMENTAL SOLUTIONS

2012 ◽  
Vol 11 (1-2) ◽  
pp. 53
Author(s):  
L. P. Aoki ◽  
M. G. Maunsell ◽  
H. E. Schulz
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Fluid Velocity ◽  
Flow Analysis ◽  
Test Chamber ◽  
Cross Product ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Vector Density ◽  
The Magnetic Field

This article examines a rectangular closed circuit filled with an electrolyte fluid, known as macro pumps, where a permanent magnet generates a magnetic field and electrodes generate the electric field in the flow. The fluid conductor moves inside the circuit under magnetohydrodynamic effect (MHD). The MHD model has been derived from the Navier Stokes equation and coupled with the Maxwell equations for Newtonian incompressible fluid. Electric and magnetic components engaged in the test chamber assist in creating the propulsion of the electrolyte fluid. The electromagnetic forces that arise are due to the cross product between the vector density of induced current and the vector density of magnetic field applied. This is the Lorentz force. Results are present of 3D numerical MHD simulation for newtonian fluid as well as experimental data. The goal is to relate the magnetic field with the electric field and the amounts of movement produced, and calculate de current density and fluid velocity. An u-shaped and m-shaped velocity profile is expected in the flows. The flow analysis is performed with the magnetic field fixed, while the electric field is changed. Observing the interaction between the fields strengths, and density of the electrolyte fluid, an optimal configuration for the flow velocity isdetermined and compared with others publications.

scholarly journals Numerical Simulation on Aerodynamics of Multi-Element Airfoil with Drooped Spoiler in Ground Effect

2019 ◽  
Vol 37 (1) ◽  
pp. 167-176
Author(s):  
Jiang Liu ◽  
Junqiang Bai ◽  
Guozhu Gao ◽  
Min Chang ◽  
Nan Liu
Keyword(s):  
Lift Coefficient ◽  
Angle Of Attack ◽  
Ground Effect ◽  
Lower Surface ◽  
Navier Stokes ◽  
High Angle ◽  
High Angle Of Attack ◽  
Ride Height ◽  
Navier Stokes Equation ◽  
Sst Turbulence Model

By using the finite volume method and k-ω SST turbulence model to solve the Reynolds Average Navier-Stokes equation and using the slipping wall to simulate the relative movement of the ground, the ground effect on the aerodynamic characteristic of multi-element airfoil with drooped spoiler is investigated numerically, and the reason why the lift coefficient decreased in ground effect is analyzed. The results indicate that, with the reduction in ride height, the lift and the drag decrease and the lift-drag ratio increases for the multi-element airfoil; the amplitude of the reduction in the lift coefficient increases with the reduction in ride height and the increase in the angle of attack, the maximum of lift coefficient can be reduced by about 22%; with the effect of ground, the losses of suction at upper surface make the lift decrease, the increases of pressure at lower surface make the lift increase, the variation of the lift coefficient for the main wing caused by the former is more than three times that of the latter. Analyzing the reason why the lift coefficient decreases showed that:on the one hand, ground effect on the lift coefficient for clean airfoil is changed with the range of angle of attack. For the low-to-moderate angle of attack, the lift coefficient increases; for the high angle of attack, the lift coefficient decreases. But multi-element airfoil works in the takeoff and landing stage for the high angle of attack, which causes the reduction of the lift coefficient in ground effect. On the other hand, the increase of the lift coefficient caused by the deflection of spoiler decreases with the reduction in ride height and the maximum reduction can be about 50%, which illustrates that ground effect makes interaction of the front and back section for the multi-element airfoil weak, resulting in further decreasing the coefficient for the multi-element airfoil.

Existence of self-similar solutions of the two-dimensional Navier–Stokes equation for non-Newtonian fluids

2019 ◽  
Vol 26 (1/2) ◽  
pp. 167-178 ◽  
Author(s):  
Dongming Wei ◽  
Samer Al-Ashhab
Keyword(s):  
Newtonian Fluids ◽  
Navier Stokes ◽  
Classical Solutions ◽  
Two Dimensional ◽  
Infinite Domain ◽  
Navier Stokes Equation ◽  
Continuity Equations ◽  
Self Similar ◽  
Similar Solutions ◽  
Two Parameters

The reduced problem of the Navier–Stokes and the continuity equations, in two-dimensional Cartesian coordinates with Eulerian description, for incompressible non-Newtonian fluids, is considered. The Ladyzhenskaya model, with a non-linear velocity dependent stress tensor is adopted, and leads to the governing equation of interest. The reduction is based on a self-similar transformation as demonstrated in existing literature, for two spatial variables and one time variable, resulting in an ODE defined on a semi-infinite domain. In our search for classical solutions, existence and uniqueness will be determined depending on the signs of two parameters with physical interpretation in the equation. Illustrations are included to highlight some of the main results.

COMPARISON OF GAS SLIP MODELS WITH SOLUTIONS OF LINEARIZED BOLTZMANN EQUATION AND DIRECT SIMULATION OF MONTE CARLO METHOD

2007 ◽  
Vol 18 (02) ◽  
pp. 203-216 ◽  
Author(s):  
G. H. TANG ◽  
Y. L. HE ◽  
W. Q. TAO
Keyword(s):  
Friction Factor ◽  
Flow Rate ◽  
Slip Flow ◽  
Flow Analysis ◽  
Slip Boundary Condition ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Slip Boundary ◽  
Slip Regime ◽  
Linearized Boltzmann Equation

Analytical solutions of the Navier–Stokes equation based on a locally fully-developed flow assumption with various gas slip models are presented and comparisons for velocity profile, flow rate, friction factor, and pressure distribution are performed. The effect of the second-order coefficient in the slip boundary condition becomes significant as the Knudsen number increases. Most slip models are limited to slip regime or marginally transition regime and break down around Kn = 0.1 while Sreekanth's model, followed by Mitsuya's model, gives a good agreement with the linearized Boltzmann solutions from slip regime up to Kn = 2 for flow rate and friction factor predictions. These two models should be of great use for slip flow analysis in micro-electro-mechanical systems (MEMS) and, in particular, in situations where the flow rate and flow resistance are of interest.

scholarly journals DERIVATION OF NAVIER STOKES EQUATION IN ROTATIONAL FRAME FOR ENGINEERING FLOW ANALYSIS

2021 ◽  
pp. 100096
Author(s):  
Sananth H. Menon ◽  
Ramachandra Rao A ◽  
Jojo Mathew ◽  
Jayaprakash J
Keyword(s):  
Stokes Equation ◽  
Flow Analysis ◽  
Navier Stokes ◽  
Navier Stokes Equation

Two-Phase Flow Analysis With the Two-Fluid MPS Method: I — Analysis of the Forced Convection Boiling

2003 ◽  
Author(s):  
Hideki Horie ◽  
Yuichi Yamamoto ◽  
Noriyuki Shirakwa
Keyword(s):  
Forced Convection ◽  
Differential Operators ◽  
Two Phase Flow ◽  
Particle Interaction ◽  
Flow Analysis ◽  
Navier Stokes ◽  
Phase Flow ◽  
Two Phase ◽  
Navier Stokes Equation ◽  
Two Fluid

A particle interaction method called MPS (the Moving Particle Semi-implicit method), which formulates the differential operators in Navier-Stokes’ equation as interactions between particles characterized by a kernel function, has been developed in recent years. We have extended this method to a two-fluid system with a potential-type surface tension in order to analize the two-phase flow without experimental correlation. This extended method (Two-Fluid MPS: TF_MPS) was successfully applied to a forced convection boiling experiment.

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