scholarly journals Computational Fluid Dynamics Study of Swimmer's Hand Velocity, Orientation, and Shape: Contributions to Hydrodynamics

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Milda Bilinauskaite ◽  
Vishveshwar Rajendra Mantha ◽  
Abel Ilah Rouboa ◽  
Pranas Ziliukas ◽  
Antonio Jose Silva
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fluid Flow ◽  
Steady State ◽  
Drag Force ◽  
3D Models ◽  
Hydrodynamic Characteristics ◽  
Front Crawl ◽  
Drag Forces ◽  
Computational Fluid Dynamics Cfd

The aim of this paper is to determine the hydrodynamic characteristics of swimmer’s scanned hand models for various combinations of both the angle of attack and the sweepback angle and shape and velocity of swimmer's hand, simulating separate underwater arm stroke phases of freestyle (front crawl) swimming. Four realistic 3D models of swimmer's hand corresponding to different combinations of separated/closed fingers positions were used to simulate different underwater front crawl phases. The fluid flow was simulated using FLUENT (ANSYS, PA, USA). Drag force and drag coefficient were calculated using (computational fluid dynamics) CFD in steady state. Results showed that the drag force and coefficient varied at the different flow velocities on all shapes of the hand and variation was observed for different hand positions corresponding to different stroke phases. The models of the hand with thumb adducted and abducted generated the highest drag forces and drag coefficients. The current study suggests that the realistic variation of both the orientation angles influenced higher values of drag, lift, and resultant coefficients and forces. To augment resultant force, which affects swimmer's propulsion, the swimmer should concentrate in effectively optimising achievable hand areas during crucial propulsive phases.

A Computational Fluid Dynamics Study of Propulsion Due to the Orientation Effects of Swimmer’s Hand

2013 ◽  
Vol 29 (6) ◽  
pp. 817-823 ◽  
Author(s):  
Milda Bilinauskaite ◽  
Vishveshwar R. Mantha ◽  
Abel I. Rouboa ◽  
Pranas Ziliukas ◽  
António J. Silva
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Steady State ◽  
Angle Of Attack ◽  
Mean Value ◽  
Hydrodynamic Characteristics ◽  
Front Crawl ◽  
Hand Model ◽  
The Mean ◽  
Drag And Lift

The aim of the article is to determine the hydrodynamic characteristics of a swimmer’s scanned hand model for various possible combinations of both the angle of attack and the sweepback angle, simulating separate underwater arm stroke phases of front crawl swimming. An actual swimmer’s hand with thumb adducted was scanned using an Artec L 3D scanner. ANSYS Fluent code was applied for carrying out steady-state computational fluid dynamics (CFD) analysis. The hand model was positioned in nine different positions corresponding to the swimmer’s hand orientations (angle of attack and sweepback angle) and velocities observed during the underwater hand stroke of front crawl. Hydrodynamic forces and coefficients were calculated. Results showed significantly higher drag coefficient values in the pull phase, when compared with previous studies under a steady-state flow condition. The mean value of the ratio of drag and lift coefficients was 2.67 ± 2.3 in underwater phases. The mean value of the ratio of drag and lift forces was 2.73 ± 2.4 in underwater phases. Moreover, hydrodynamic coefficients were not almost constant throughout different flow velocities, and variation was observed for different hand positions corresponding to different stroke phases. The current study suggests that the realistic variation of both the orientation angles influenced higher values of drag, lift and resultant coefficients and forces.

CFD Leakage Predictions of Unworn and Worn Labyrinth Seals With and Without Tooth Axial Offset

2017 ◽  
Author(s):  
Hasham H. Chougule ◽  
Alexander Mirzamoghadam
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Modeling ◽  
Steady State ◽  
Flow Field ◽  
Labyrinth Seals ◽  
Small Clearance ◽  
Total Leakage ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Deflection

The objective of this study is to develop a Computational Fluid Dynamics (CFD) based methodology for analyzing and predicting leakage of worn or rub-intended labyrinth seals during operation. The simulations include intended tooth axial offset and numerical modeling of the flow field. The purpose is to predict total leakage through the seal when an axial tooth offset is provided after the intended/unintended rub. Results indicate that as expected, the leakage for the in-line worn land case (i.e. tooth under rub) is higher compared to unworn. Furthermore, the intended rotor/teeth forward axial offset/shift with respect to the rubbed land reduces the seal leakage. The overall leakage of a rubbed seal with axial tooth offset is observed to be considerably reduced, and it can become even less than a small clearance seal designed not to rub. The reduced leakage during steady state is due to a targeted smaller running gap because of tooth offset under the intended/worn land groove shape, higher blockages, higher turbulence and flow deflection as compared to worn seal model without axial tooth offset.

Numerical Analysis of Flow Over the NASA Common Research Model Using the Academic Computational Fluid Dynamics Code Galatea

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Georgios N. Lygidakis ◽  
Ioannis K. Nikolos
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Computational Study ◽  
Research Model ◽  
Drag Forces ◽  
Efficient Prediction ◽  
Wind Tunnel Data ◽  
Computational Fluid Dynamics Cfd ◽  
Lift And Drag

A recently developed academic computational fluid dynamics (CFD) code, named Galatea, is used for the computational study of fully turbulent flow over the NASA common research model (CRM) in a wing-body configuration with and without horizontal tail. A brief description of code's methodology is included, while attention is mainly directed toward the accurate and efficient prediction of pressure distribution on wings' surfaces as well as of computation of lift and drag forces against different angles of attack, using an h-refinement approach and a parallel agglomeration multigrid scheme. The obtained numerical results compare close with both the experimental wind tunnel data and those of reference solvers.

Numerical Simulations of the Non-Newtonian Blood Blow in Human Abdominal Artery Based on Reverse Engineering

2011 ◽  
Vol 140 ◽  
pp. 195-199 ◽  
Author(s):  
Jin You YANG ◽  
Yang Hong
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Flow ◽  
Fluid Flow ◽  
Reverse Engineering ◽  
Power Law ◽  
Cardiac Cycle ◽  
Hemodynamic Parameters ◽  
Human Artery ◽  
Computational Fluid Dynamics Cfd

The method that combined the reverse engineering based on CT medical images and computational fluid dynamics (CFD) was used to perform simulation the Non-Newtonian blood fluid flow in human abdominal artery, then analyzed the hemodynamic condition about the bifurcation of human abdominal artery. A Non-Newtonian blood model (the Generalised Power Law) was used to study the hemodynamic parameters during entire cardiac cycle. Calculated results for the Non-Newtonian blood flow show us the methods performed in this study is suitable for numerical simulating the blood flow in human artery and investigating the relation between hemodynamic factors and vascular disease.

Three-Dimensional CFD Analysis of Gas Mixing in Large Volumes

2001 ◽  
Author(s):  
Brian L. Smith
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Steady State ◽  
Three Dimensional ◽  
Air Injection ◽  
Cfd Analysis ◽  
Gas Mixing ◽  
Air Mixing ◽  
Computational Fluid Dynamics Cfd ◽  
Pure Steam

Abstract The paper describes three-dimensional Computational Fluid Dynamics (CFD) calculations undertaken in support of analyses of steam/air mixing which takes place in the drywell volumes of the 1/40th-scale ESBWR1 mock-up facility PANDA under conditions of symmetric steam/air injection and asymmetric outflow. Steady-state simulations for pure steam conditions illustrate how the flow streams mix to ensure balanced outflow conditions to the condensers. A transient calculation has also been performed to examine how air released from solution in the PANDA boiler would ultimately accumulate in the separate condenser units. Results provide a possible explanation for the rundown in performance of one of the condensers which was repeatedly observed in some of the PANDA tests.

The Practical Application of CFD in the Design of Industrial Centrifugal Compressors

2000 ◽  
Author(s):  
James M. Sorokes ◽  
Bradley R. Hutchinson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fluid Flow ◽  
Gas Turbine ◽  
Flow Fields ◽  
Practical Application ◽  
Jet Engine ◽  
Flow Problems ◽  
Computational Fluid Dynamics Cfd ◽  
Complex Fluid

Abstract In the development of industrial turbomachinery, the aerodynamic designer is faced with many complex fluid flow problems. In the mid to late 1980’s, Computational Fluid Dynamics (CFD) software was developed to assist in the solution of these flow fields. Initially applied only by high end gas turbine or jet engine designers, these sophisticated tools eventually found their way to engineers at industrial turbomachinery manufacturers. However, it has only been in the last five to ten years that industrial users have begun to make more widespread use of CFD. There are a variety of reasons for this slow adoption.

Achieving high parallel performance for an unstructured unsteady turbomachinery CFD code

2007 ◽  
Vol 111 (1117) ◽  
pp. 185-193 ◽  
Author(s):  
N. Hills
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Steady State ◽  
Load Balancing ◽  
Unstructured Mesh ◽  
Test Cases ◽  
Hexahedral Mesh ◽  
Parallel Performance ◽  
Computational Fluid Dynamics Cfd ◽  
Work Done

This paper describes the work done to achieve high parallel performance for an unstructured, unsteady turbomachinery computational fluid dynamics (CFD) code. The aim of the work described here is to be able to scale problems to the thousands of processors that current and future machine architectures will provide. The CFD code is in design use in industry and is also used as a research tool at a number of universities. High parallel scalability has been achieved for a range of turbomachinery test cases, from steady-state hexahedral mesh cases to fully unsteady unstructured mesh cases. This has been achieved by a combination of code modification and consideration of the parallel partitioning strategy and resulting load balancing. A sliding plane option is necessary to run fully unsteady multistage turbomachinery test cases and this has been implemented within the CFD code. Sample CFD calculations of a full turbine including parts of the internal air system are presented.

scholarly journals Data-Driven Computational Fluid Dynamics Model for Predicting Drag Forces on Truck Platoons

2021 ◽  
Author(s):  
Hadi Meidani ◽  
◽  
Amir Kazemi ◽  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fuel Consumption ◽  
Data Driven ◽  
Dynamics Model ◽  
Drag Forces ◽  
Consumption Reduction ◽  
Energy Economy ◽  
Computational Fluid Dynamics Cfd ◽  
Large Systems

Fuel-consumption reduction in the truck industry is significantly beneficial to both energy economy and the environment. Although estimation of drag forces is required to quantify fuel consumption of trucks, computational fluid dynamics (CFD) to meet this need is expensive. Data-driven surrogate models are developed to mitigate this concern and are promising for capturing the dynamics of large systems such as truck platoons. In this work, we aim to develop a surrogate-based fluid dynamics model that can be used to optimize the configuration of trucks in a robust way, considering various uncertainties such as random truck geometries, variable truck speed, random wind direction, and wind magnitude. Once trained, such a surrogate-based model can be readily employed for platoon-routing problems or the study of pavement performance.

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