scholarly journals Deforming grid generation for numerical simulations of fluid dynamics in sliding vane rotary machines

2017 ◽  
Vol 112 ◽  
pp. 180-191 ◽  
Author(s):  
Giuseppe Bianchi ◽  
Sham Rane ◽  
Ahmed Kovacevic ◽  
Roberto Cipollone
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulations ◽  
Grid Generation ◽  
Rotary Machines

Pneumatic pulsator design as an example of numerical simulations in engineering applications

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Krzysztof Wołosz ◽  
Jacek Wernik
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Cast Iron ◽  
Numerical Simulations ◽  
Stress Analysis ◽  
Aluminium Alloy ◽  
Loose Material ◽  
Engineering Applications ◽  
Pressure Losses ◽  
Pneumatic Impact

AbstractThe paper presents the part of the investigation that has been carried out in order to develop the pneumatic pulsator which is to be employed as an unblocking device at lose material silo outlets. The part of numerical simulation is reported. The fluid dynamics issues have been outlined which are present during supersonic airflow thought the head of the pulsator. These issues describe the pneumatic impact phenomenon onto the loose material bed present in the silo to which walls the pulsator is assembled. The investigation presented in the paper are industrial applicable and the result is the working prototype of the industrial pneumatic pulsator. The numerical simulation has led to change the piston shape which is moving inside the head of the pulsator, and therefore, to reduce the pressure losses during the airflow. A stress analysis of the pulsator controller body has been carried out while the numerical simulation investigation part of the whole project. The analysis has made possible the change of the controller body material from cast iron to aluminium alloy.

Potential enstrophy in stratified turbulence

2013 ◽  
Vol 722 ◽  
Author(s):  
Michael L. Waite
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulations ◽  
Reynolds Numbers ◽  
Direct Numerical Simulations ◽  
Quadratic Approximation ◽  
Stratified Turbulence ◽  
Geophysical Fluid Dynamics ◽  
Quadratic Part ◽  
Flow Variables ◽  
Potential Enstrophy

AbstractDirect numerical simulations are used to investigate potential enstrophy in stratified turbulence with small Froude numbers, large Reynolds numbers, and buoyancy Reynolds numbers ($R{e}_{b} $) both smaller and larger than unity. We investigate the conditions under which the potential enstrophy, which is a quartic quantity in the flow variables, can be approximated by its quadratic terms, as is often done in geophysical fluid dynamics. We show that at large scales, the quadratic fraction of the potential enstrophy is determined by $R{e}_{b} $. The quadratic part dominates for small $R{e}_{b} $, i.e. in the viscously coupled regime of stratified turbulence, but not when $R{e}_{b} \gtrsim 1$. The breakdown of the quadratic approximation is consistent with the development of Kelvin–Helmholtz instabilities, which are frequently observed to grow on the layerwise structure of stratified turbulence when $R{e}_{b} $ is not too small.

EVALUATION OF LEFT VENTRICULAR FILLING PRESSURE USING NUMERICAL MODELING

2020 ◽  
Vol 20 (07) ◽  
pp. 2050043
Author(s):  
A. BENFOULA ◽  
L. HAMZA CHERIF ◽  
K. N. HAKKOUM
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Left Ventricle ◽  
Numerical Simulations ◽  
Left Ventricular ◽  
Filling Pressure ◽  
Proof Of Concept ◽  
Ventricular Dilation ◽  
Ventricular Filling Pressure ◽  
Ventricular Filling

The main objective of this work is to study the effect of blood pressure and viscosity on flow in a pathological and healthy anatomy. The method chosen for this project is the numerical simulation of fluid dynamics. First, a radiological database from Tlemcen hospital was studied in order to select a patient whose aortic anatomy is representative of the pathology studied in this research project. The left ventricle was segmented using SolidWork software. The exported data made it possible to model this geometry on Comsol software. The geometry has been idealized to make it comparable to a given healthy left ventricle geometry and present the main parameters which influence the ventricular hemodynamics. A first series of numerical simulations made it possible to highlight the hemodynamic disturbances associated with the pathology of interest and described extensively in the literature. A second series of numerical simulations made it possible to model the effect of blood viscosity on flow. All the results obtained, the modeling of the left ventricle, must be valid experimentally. This study therefore does not completely justify the treatment of ventricular dilation with a flow modulator but constitutes an important first step towards a proof of concept.

Geometry-Based Hyperbolic Grid Generation for Computational Fluid Dynamics

AIAA Journal ◽  
2001 ◽  
Vol 39 (8) ◽  
pp. 1631-1633 ◽  
Author(s):  
S. Anil Lal ◽  
B. V. S. S. S. Prasad ◽  
N. Sitaram
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Grid Generation

Vehicles Aerodynamics while Crossing each other on Road Based on Computational Fluid Dynamics

2010 ◽  
Vol 29-32 ◽  
pp. 1344-1349 ◽  
Author(s):  
Zhe Zhang ◽  
Ying Chao Zhang ◽  
Jie Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Simulations ◽  
Aerodynamic Force ◽  
The Other ◽  
Moving Mesh ◽  
Aerodynamic Coefficients ◽  
Paper Report ◽  
Vehicle Aerodynamics ◽  
Simulation Results

When vehicles run on road, they will be overtaken, cross by other vehicles or be impacted by crosswind. The other events of overtaking and in crosswind were investigated more deeply. A few of paper report the state of the research on this problem. Until now there are no any wind tunnel and road tests to study on road vehicle aerodynamics while crossing each other. Some numerical simulations were carried out by adopting technology of sliding interface and moving mesh. The method of numerical simulations was narrated in detail. The transient process of vehicles crossing each other was realized. Then the trends of aerodynamic coefficients changing were obtained from the flow field of simulation results. The quantificational changing of vehicles aerodynamic coefficients was obtained when they cross each other. The vehicles are sedan and coach. The simulation results indicated that the all aerodynamic coefficients of two vehicles changed large. The aerodynamic force was important to the vehicles’ handling stability when they cross each other.

Fluid Dynamics Measurements and Numerical Simulations Around a Circular Cylinder Impinged by a Submerged Slot Jet of Air

2003 ◽  
Author(s):  
F. Gori ◽  
I. Petracci
Keyword(s):  
Fluid Dynamics ◽  
Reynolds Number ◽  
Wind Tunnel ◽  
Circular Cylinder ◽  
Numerical Simulations ◽  
Hydraulic Diameter

Submerged slot jets of air, impinging onto a cylinder, have been investigated with a new wind tunnel, which realizes low turbulence intensities at the slot exit. The hot anemometry has been used to measure velocity and turbulence across the section of the jet, at several distances from the slot exit, up to the impinged cylinder. The cylinder has been set at two distances from the slot exit, equal to 4 and 6 times the slot height. The Reynolds number of the jet is equal to 23,300, based on the hydraulic diameter of the slot.

Experimental Measurements and Numerical Modeling for the Air-Mist Cooling of a Heated Cylinder

2008 ◽  
Author(s):  
Roy J. Issa ◽  
Emily M. Hunt ◽  
Freddie J. Davis
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Numerical Simulations ◽  
Droplet Size ◽  
Nucleate Boiling ◽  
Back Surface ◽  
Cylinder Surface ◽  
Experimental Measurements ◽  
Heated Cylinder ◽  
Transportation Process

Experimental measurements and numerical simulations are conducted to investigate the effect of mist on the spray heat transfer and fluid dynamics in the cooling of a low-carbon steel cylindrical surface heated to the nucleate boiling temperature range. Multiple tests are performed to investigate the effect of the droplet size, and liquid-to-air loading on the spray heat transfer along the circumference of the annulus cylinder. Infrared imaging is used to capture the effect of the spray flow conditions on the droplets transportation process around the heated cylinder. A computational fluid dynamics model is also developed to simulate the spray transportation process, droplets impaction and evaporation over the cylinder surface. The model takes into consideration droplet-to-surface interaction and water-film accumulation on the surface. Simulation results show the wetting of the cylinder depends on the droplet size and liquid-to-air loading. The smaller the droplets, the closer to the surface they remain. For high liquid-to-air loadings and high air velocities, droplet wetting of the cylinder back surface dramatically increases due to the increase in the flow turbulence. An overall good agreement is observed between the experimental measurements, numerical simulations and the thermal images. The results of this study shall lead to a better understanding of the multiphase heat transfer enhancement that plays an important role in the design of heat exchangers using multiphase cooling.

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