scholarly journals Hydrodynamical effect of parallelly swimming fish using computational fluid dynamics method

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0250837
Author(s):  
Keisuke Doi ◽  
Tsutomu Takagi ◽  
Yasushi Mitsunaga ◽  
Shinsuke Torisawa
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Flow Speed ◽  
The Body ◽  
Fluid Force ◽  
Fish Model ◽  
Swimming Motion ◽  
Computational Fluid Dynamics Analysis ◽  
Swimming Efficiency

Fish form schools because of many possible reasons. However, the hydrodynamic mechanism whereby the energy efficiency of fish schools is improved still remains unclear. There are limited examples of fish models based on actual swimming movements using simulation, and the movements in existing models are simple. Therefore, in this study, we analyzed the swimming behavior of Biwa salmon (Oncorhynchus sp., a salmonid fish) using image analyses and formulated its swimming motion. Moreover, computational fluid dynamics analysis was carried out using the formulated swimming motion to determine the fluid force acting on the fish body model with real fish swimming motion. The swimming efficiency of the fish model under parallel swimming was obtained from the calculated surrounding fluid force and compared for different neighboring distances. The flow field around the fish model was also examined. The swimming efficiency of two fish models swimming parallelly was improved by approximately 10% when they were separated by a distance of 0.4L, where L is the total length of the model. In addition, the flow field behind the fish body was examined under both inphase and antiphase conditions and at inter-individual distances of 0.8L and 1.2L. The apparent flow speed in the distance range of 0.5–2.0L from the midpoint of the snouts of the two individuals was lower than the swimming speed. The pressure distribution on the fish model showed an elevated pressure at the caudal fin. Interestingly, we obtained an isopleth map similar to that of a caudal peduncle. To avoid a negative thrust, the aft part of the body must be thin, as shown in the isopleth map obtained in this study.

scholarly journals A Computational Fluid Dynamics Analysis of an Ideal Anguilliform Swimming Motion

2017 ◽  
Vol 51 (6) ◽  
pp. 21-32
Author(s):  
Brandon M. Taravella ◽  
Charles T. Rogers
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fluid Velocity ◽  
The Body ◽  
Current Work ◽  
Ansys Fluent ◽  
Induced Drag ◽  
Swimming Motion ◽  
Computational Fluid Dynamics Analysis ◽  
Body Formulation

AbstractResearchers have been studying swimming motions of various fishes for numerous years. The scope of the current work is to validate the results of an ideal anguilliform swimming motion developed by Vorus and Taravella (2011) by modeling the motion in a commercially available Computational Fluid Dynamics (CFD) code. The ideal swimming motion developed by Vorus and Taravella (2011) shows that thrust can be generated by an anguilliform swimmer without producing wake-induced drag. In the current work, ANSYS Fluent was used to discretize and solve Euler's equation and the continuity conservation. The results for fluid velocity on the body of the anguilliform show an average agreement within ±3% to the potential flow slender body formulation of Vorus and Taravella (2011). There is also no induced circulation in the wake of the anguilliform in the CFD solution, which confirms the absence of wake-induced drag. The results suggest that it is plausible for an undulating body to produce thrust that is purely inertial and is produced by body accelerations acting through hydrodynamic added mass.

scholarly journals Computational fluid dynamics analysis of the influence of injection nozzle lateral outflow on the performance of Ranque-Hilsch vortex tube

2014 ◽  
Vol 18 (4) ◽  
pp. 1191-1201 ◽  
Author(s):  
Nader Pourmahmoud ◽  
Alireza Izadi ◽  
Amir Hassanzadeh ◽  
Ashkan Jahangiramini
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Vortex Tube ◽  
Operating Conditions ◽  
Energy Separation ◽  
Physical Parameters ◽  
Dynamics Analysis ◽  
Computational Domain ◽  
Computational Fluid Dynamics Analysis

In this article computational fluid dynamics analysis of a three-dimensional compressible and turbulent flow has been carried out through a vortex tube. The standard k-? turbulence model is utilized in order to simulate an axisymmetric computational domain. The numerical simulation has focused on the energy separation and flow field patterns of a somewhat nonconventional vortex tube, which is on the basis of creating an external hole at the end of each nozzle. According to the selected nozzles geometry, some of unfavorable phenomena such as shock wave, high pressure regions and appearing of unsymmetrical rotating flow patterns in the vortex chamber would be recovered significantly. In this way the physical parameters of flow field are derived under different both inlet mass flow rates and outlet pressures of nozzles hole (OPH). The results show that increasing OPH value enhanced the cooling capacity of machine in the most of operating conditions.

Computational Fluid Dynamics Analysis of the Flow Field Around Spark Gap in a Two Valve Engine

2014 ◽  
Author(s):  
Leonardo Fonseca ◽  
Raphael Meireles ◽  
Rudolf Huebner ◽  
Matheus Carvalho ◽  
Ramon Molina
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Dynamics Analysis ◽  
Spark Gap ◽  
Computational Fluid Dynamics Analysis ◽  
Valve Engine

Evaluation of Jet Impact Region and Fluid Force Generated From Ruptured Pipes: 2 — Evaluation of Fluid Force Using Computational Fluid Dynamics Analysis

2016 ◽  
Author(s):  
Shiro Takahashi ◽  
Qiang Xu ◽  
Noriyuki Takamura ◽  
Ryo Morita ◽  
Yuta Uchiyama ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nuclear Power ◽  
Power Plants ◽  
Jet Impingement ◽  
Cfd Analysis ◽  
Fluid Force ◽  
Free Jet ◽  
Jet Impact ◽  
Computational Fluid Dynamics Analysis

Nuclear power plants are designed to avoid damage to their safety installations because of jet impingement when a pipe is ruptured. We have investigated evaluation methods for the design basis of protection of plants against effects of postulated pipe rupture using computational fluid dynamics (CFD) analysis. The steam jet tests obtained using particle image velocimetry (PIV) were conducted in order to verify the CFD analysis. Spread of steam jets could be visualized and the shapes of the steam jets obtained by analysis were almost the same as those by tests. The spread angle of free jet was investigated using CFD analysis. We also measured jet fluid force when a cylindrical structure was installed downstream from the jet nozzle. Steam jet fluid force obtained by analysis was almost the same as that by tests. We judged the CFD analysis to be applicable to evaluation of jet fluid force generated from ruptured pipes.

scholarly journals Numerical Simulation on Flow Field and Design Optimization of a Generator Unit Based on Computational Fluid Dynamics Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yingying Xu ◽  
Libin Tan ◽  
Yuejin Yuan ◽  
Man Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Design Optimization ◽  
Field Analysis ◽  
Dynamics Analysis ◽  
Computational Fluid Dynamics Analysis ◽  
Generator Unit ◽  
Cooling Air ◽  
Conventional Type

Achieving an optimal cooling of the generator unit is indispensable for high working performance. In this work, computational fluid dynamics analysis on the flow field of the conventional type and silent type of the S688CCS series generator unit is conducted, and design optimization of the generator unit with poor cooling is studied based on flow field analysis results. Flow field simulation results indicate that the total cooling air quantity of the silent type generator unit is lower than that of the conventional type generator unit, and the cooling air quantity of the radiator is also lower than that of the conventional type generator unit, which is not conductive for the cooling of the silent type generator unit. The flow field optimization is achieved by adopting the single variable control method to improve the structure of the fan cover, silent components for silence, adjacent structure, and air inlet grille. The corresponding structure optimization scheme is put forward. After optimization, the air quantity for the cooling radiator of the silent type generator unit is 44.33% higher than that of its original structure, and the total cooling air quantity is higher than that of the conventional type generator unit. The research results in this work can provide a theoretical basis for the design of the cooling air flow path of generator units for achieving an optimal cooling performance.

In-Cylinder Flow Computational Fluid Dynamics Analysis of a Four-Valve Spark Ignition Engine: Comparison Between Steady and Dynamic Tests

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Damian E. Ramajo ◽  
Norberto M. Nigro
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Steady Flow ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Mean Flow ◽  
Dynamic Simulations ◽  
Computational Fluid Dynamics Analysis ◽  
Cylinder Flow

Numerical and experimental techniques were applied in order to study the in-cylinder flow field in a commercial four-valve per cylinder spark ignition engine. Investigation was aimed at analyzing the generation and evolution of tumble-vortex structures during the intake and compression strokes, and the capacity of this engine to promote turbulence enhancement during tumble degradation at the end of the compression stroke. For these purposes, three different approaches were analyzed. First, steady flow rig tests were experimentally carried out, and then reproduced by computational fluid dynamics (CFD). Once CFD was assessed, cold dynamic simulations of the full engine cycle were performed for several engine speeds (1500 rpm, 3000 rpm, and 4500 rpm). Steady and cold dynamic results were compared in order to assess the feasibility of the former to quantify the in-cylinder flow. After that, combustion was incorporated by means of a homogeneous heat source, and dynamic boundary conditions were introduced in order to approach real engine conditions. The combustion model estimates the burning rate as a function of some averaged in-cylinder flow variables (temperature, pressure, turbulent intensity, and piston position). Results were employed to characterize the in-cylinder flow field of the engine and to establish similarities and differences between the three performed tests that are currently used to estimate the engine mean flow characteristics (steady flow rig, and cold and real dynamic simulations).

Computational Fluid Dynamics Analysis for Flow Field of Radiator Air Intake in the Powertrain Compartment

2013 ◽  
Vol 464 ◽  
pp. 171-175
Author(s):  
Lin Lin Song ◽  
Wei Zheng Zhang ◽  
Yuan Fu Cao ◽  
Ya Lei Zeng
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Air Flow ◽  
Flow Distribution ◽  
Heat Transfer Analysis ◽  
Wind Speeds ◽  
Computational Fluid Dynamics Analysis ◽  
Cooling Air Flow ◽  
Cooling Air

A computational fluid dynamics (CFD) model of tank powertrain compartment was constructed for cooling air flow and heat transfer analysis. The key points temperatures of the powertrain compartment were tested, and the numerical values have a good agreement with the measurement datas. Detailed cooling air flow field distributing characteristic through radiators in the powertrain compartment were obtained through numerical method, with different fan speeds and ambient wind speeds. These results can provide the basis for the choice of the fan speed on specific condition and the air flow distribution of the radiator.

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