Instabilities in Source-Sink Flows for Rotating Machines: Numerical Results

1994 ◽  
Author(s):  
P. Maubert ◽  
A. Chaouche ◽  
Anthony Randriamampianina ◽  
Emilia Crespo del Arco ◽  
Patrick Bontoux
Keyword(s):  
Numerical Results ◽  
Rotating Machines ◽  
Source Sink

Some Numerical Results on Wave Resistance of a Point Dipole

1975 ◽  
Vol 19 (03) ◽  
pp. 133-138
Author(s):  
Chuan Lee
Keyword(s):  
Free Surface ◽  
Wave Resistance ◽  
Numerical Results ◽  
Point Dipole ◽  
Numerical Accuracy ◽  
Surface Theory ◽  
Wave Profiles ◽  
Source Sink

The distribution of singularities (that is, source, sink, and dipole) representing a ship's hull has played an important role in the study of wave resistance in naval hydrodynamics. Based on the theoretical wave resistance formula from linearized free-surface theory, six different wave resistance expressions in terms of three wave components along a longitudinal cut parallel to the ship's course are presented. To demonstrate the numerical accuracy of these wave resistance expressions, the analysis has been applied to the theoretical wave profiles generated by a submerged point dipole, and the results are compared with the known theoretical value.

scholarly journals Numerical Simulation For Bioconvectional Flow of Burger Nanofluid With Effects of Activation Energy and Exponential Heat Source/Sink Over an Inclined Wall Under The Swimming Microorganisms

2021 ◽  
Author(s):  
Hassan Waqas ◽  
Umar Farooq ◽  
Aqsa Ibrahim ◽  
Zahir Shah ◽  
Poom Kumam
Keyword(s):  
Heat Transfer ◽  
Differential Equation ◽  
Activation Energy ◽  
Numerical Results ◽  
Solid Particles ◽  
Nonlinear Thermal Radiation ◽  
Liquid Component ◽  
Source Sink ◽  
Bioconvective Flow ◽  
The Impact

Abstract A nanofluid is a combination of a normal liquid component and tiny-solid particles, in which the nanomaterials are immersed in the liquid. The dispersion of solid particles into yet another host fluid will extremely increase the heat capacity of the nanoliquids, and an increase of heat efficiency can play a significant role in boosting the rate of heat transfer of the host liquid. The current article discloses the impact of Arrhenius activation energy in the bioconvective flow of Burger nanofluid by an inclined wall. The heat transfer mechanism of Burger nanofluid is analyzed through the nonlinear thermal radiation effect. The Brownian dispersion and thermophoresis diffusions effects are also scrutinized. Established partial differential equation expressions are updated by a similarity transformation of the ordinary differential equation ODE. The numerical results are given by the built-in bvp4c function Matlab also applies the Labotto-IIIa formula for the shooting scheme. Trends with significant parameters via the flow of fluid, thermal, and solutal fields of species and the area of microorganisms are controlled. The numerical results for the current analysis are seen in the tables.

Thermophoresis and Brownian effects on natural convection of nanofluids in a square enclosure with two pairs of heat source/sink

2015 ◽  
Vol 25 (5) ◽  
pp. 1030-1046 ◽  
Author(s):  
Aminreza Noghrehabadi ◽  
Amin Samimi Behbahan ◽  
I. Pop
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Heat Source ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Numerical Results ◽  
Content Type ◽  
Source Sink

Purpose – The purpose of this paper is to study natural convection heat transfer and fluid flow in a square cavity filled with CuO-water nanofluid. Design/methodology/approach – The entire length of the bottom wall of the cavity is covered by two pairs of heat source-sink, whereas the other walls are insulated. The governing equations of fluid flow are discretized using a finite volume method with a collocated grid arrangement. The coupling between velocity and pressure is solved using the SIMPLEC and the Rhie and Chow interpolation is used to avoid the checker-board solutions for the pressure. Findings – The numerical results are reported for the effect of Rayleigh number, solid volume fraction and both presence and absence of thermophoresis and Brownian motion effects. The numerical results show an improvement in heat transfer rate for the whole range of Rayleigh numbers when Brownian and thermophoresis effects are considered. Furthermore, an increase in the Rayleigh number and nanoparticle volume fraction in both cases – when Brownian and thermophoresis effects are neglected or considered – has an excellent influence on heat transfer of nanofluids. Originality/value – The area of nanofluids is very original.

On Hydrodynamic Interaction Between Several Freely Floating Vertical Cylinders in Waves

2005 ◽  
Author(s):  
Mir Tareque Ali ◽  
Gazi Md. Khalil
Keyword(s):  
Interaction Effect ◽  
Hydrodynamic Interaction ◽  
Computer Code ◽  
Separation Distance ◽  
Numerical Results ◽  
Physical Aspect ◽  
Floating Bodies ◽  
Exciting Forces ◽  
Source Sink ◽  
Vertical Cylinders

This paper investigates the hydrodynamic interaction between several vertical cylinders freely floating in each other’s close vicinity. The physical aspect of hydrodynamic interaction is rather complicated and numerically accurate scheme is highly recommended to study this complex phenomenon. In the present study, 3D source-sink method has been adopted to determine the hydrodynamic coefficients and wave exciting forces by taking into account accurately the effect of hydrodynamic interaction among the different floating bodies. In order to check the convergence of numerical results, mean wetted surface of the floating cylinders are divided into different numbers of rectangular panels. A computer code is developed using 3D source-sink formulations and the validation of the computer code has been justified by comparing the present results with that of the published ones. In order to study the interaction effect, numerical results for a single cylinder have been compared with those of the multi-cylinder ones. The separation distance between the cylinders has been varied to examine the interaction effect for head sea condition. Finally some conclusions have been drawn on the basis of the present analysis.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

Elasto-plastic state of curve beam system subjected to complex loading

1996 ◽  
Vol 18 (4) ◽  
pp. 14-22
Author(s):  
Vu Khac Bay
Keyword(s):  
Cylindrical Shell ◽  
Solution Method ◽  
Complex Loading ◽  
Numerical Results ◽  
Elastic Solution ◽  
Plastic State ◽  
Curve Beam ◽  
Elastic State ◽  
Elastic Plastic ◽  
Beam System

Investigation of the elastic state of curve beam system had been considered in [3]. In this paper the elastic-plastic state of curve beam system in the form of cylindrical shell is analyzed by the elastic solution method. Numerical results of the problem and conclusion are given.

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