scholarly journals The Hydrodynamic Study of the Swimming Gliding: a Two-Dimensional Computational Fluid Dynamics (CFD) Analysis

2011 ◽  
Vol 29 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Daniel Marinho ◽  
Tiago Barbosa ◽  
Abel Rouboa ◽  
António Silva
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Lateral Position ◽  
Hydrodynamic Drag ◽  
Cfd Analysis ◽  
Two Dimensional ◽  
Drag Forces ◽  
Hydrodynamic Study ◽  
Computational Fluid Dynamics Cfd ◽  
The One

The Hydrodynamic Study of the Swimming Gliding: a Two-Dimensional Computational Fluid Dynamics (CFD) AnalysisNowadays the underwater gliding after the starts and the turns plays a major role in the overall swimming performance. Hence, minimizing hydrodynamic drag during the underwater phases should be a main aim during swimming. Indeed, there are several postures that swimmers can assume during the underwater gliding, although experimental results were not conclusive concerning the best body position to accomplish this aim. Therefore, the purpose of this study was to analyse the effect in hydrodynamic drag forces of using different body positions during gliding through computational fluid dynamics (CFD) methodology. For this purpose, two-dimensional models of the human body in steady flow conditions were studied. Two-dimensional virtual models had been created: (i) a prone position with the arms extended at the front of the body; (ii) a prone position with the arms placed alongside the trunk; (iii) a lateral position with the arms extended at the front and; (iv) a dorsal position with the arms extended at the front. The drag forces were computed between speeds of 1.6 m/s and 2 m/s in a two-dimensional Fluent® analysis. The positions with the arms extended at the front presented lower drag values than the position with the arms aside the trunk. The lateral position was the one in which the drag was lower and seems to be the one that should be adopted during the gliding after starts and turns.

Analysis of an Airfoil Using a Transition and Turbulence Model

2016 ◽  
Vol 819 ◽  
pp. 356-360
Author(s):  
Mazharul Islam ◽  
Jiří Fürst ◽  
David Wood ◽  
Farid Nasir Ani
Keyword(s):  
Fluid Dynamics ◽  
Boundary Layer ◽  
Computational Fluid Dynamics ◽  
Kinetic Energy ◽  
Turbulence Model ◽  
Original Version ◽  
Transitional Region ◽  
Cfd Analysis ◽  
Computational Fluid Dynamics Cfd

In order to evaluate the performance of airfoils with computational fluid dynamics (CFD) tools, modelling of transitional region in the boundary layer is very critical. Currently, there are several classes of transition-based turbulence model which are based on different methods. Among these, the k-kL- ω, which is a three equation turbulence model, is one of the prominent ones which is based on the concept of laminar kinetic energy. This model is phenomenological and has several advantageous features. Over the years, different researchers have attempted to modify the original version which was proposed by Walter and Cokljat in 2008 to enrich the modelling capability. In this article, a modified form of k-kL-ω transitional turbulence model has been used with the help of OpenFOAM for an investigative CFD analysis of a NACA 4-digit airfoil at range of angles of attack.

Computational Fluid Dynamics Techniques for Flows in Lapple Cyclone Separator

2005 ◽  
Vol 498-499 ◽  
pp. 179-185
Author(s):  
A.F. Lacerda ◽  
Luiz Gustavo Martins Vieira ◽  
A.M. Nascimento ◽  
S.D. Nascimento ◽  
João Jorge Ribeiro Damasceno ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Turbulent Flow ◽  
Reynolds Stress ◽  
Cyclone Separator ◽  
Two Dimensional ◽  
Stress Components ◽  
Computational Fluid Dynamics Cfd

A two-dimensional fluidynamics model for turbulent flow of gas in cyclones is used to evaluate the importance of the anisotropic of the Reynolds stress components. This study presents consisted in to simulate through computational fluid dynamics (CFD) package the operation of the Lapple cyclone. Yields of velocity obtained starting from a model anisotropic of the Reynolds stress are compared with experimental data of the literature, as form of validating the results obtained through the use of the Computational fluid dynamics (Fluent). The experimental data of the axial and swirl velocities validate numeric results obtained by the model.

CFD Comparison of Clearance Flow in a Rotor-Casing Assembly Using Asymmetric vs. Symmetric Lobe Rotors

2003 ◽  
Author(s):  
Bassam Abu-Hijleh ◽  
Jiyuan Tu ◽  
Aleksander Subic ◽  
Huafeng Li ◽  
Katherine Ilie
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Mesh Generation ◽  
Cfd Analysis ◽  
Air Leakage ◽  
Flow Conditions ◽  
Leakage Path ◽  
Clearance Flow ◽  
Computational Fluid Dynamics Cfd

The performance of a Rotor-Casing Assembly is influenced more by the internal air leakages than by any other thermo-fluid aspect of its behaviour. The pressure difference driving the air along a leakage path varies periodically and does so in a manner that may not be the same for every leakage path. So the distribution of leakage through the various leakage paths within the machine is important for the improvement of its performance. The total volume of air leakage and the distribution of the leakage among the different paths depend on the rotor-rotor and rotor-casing clearances as well as the geometry of the rotors’ lobes. Computational Fluid Dynamics (CFD) analysis was carried out using the FLUENT. Geometry definition, mesh generation, boundary and flow conditions, and solver parameters have all been investigated as the part of the numerical analysis. This analysis was conducted for static rotors at different positions. The results indicate that the size of the clearances as well as the geometry of the rotors’ lobes can have a significant effect on the total volume of the air leakage as well as the distribution of the leakage among the three main leakage paths. The results can be used to ascertain the proper levels of clearances to be used and the best rotor lobes geometry to be used for the practical reduction of air leakage.

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