Energy Extraction by Flexible Flapping Twin Wing

2013 ◽  
Author(s):  
Wendi Liu ◽  
Qing Xiao
Keyword(s):  
Numerical Simulation ◽  
Extraction Efficiency ◽  
System Simulation ◽  
Tidal Energy ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Energy Extraction ◽  
Navier Stokes Equation ◽  
Low Mach Number ◽  
Wide Range

The present study aims to investigate how the flexure of oscillating wings affect their hydrodynamic performance and tidal energy extraction efficiency based on their flapping motions. To achieve this goal, a numerical simulation is carried out by solving a low Mach number compressible Navier-Stokes equation for a parallel arranged twin wing system. Simulation covers a wide range of flapping frequency, various effective angles of attack, the degree of flexure and the gap between two wings. Our results indicate the improved energy efficiency with the use of flexible blade as compared to its rigid counterpart. This becomes more significant especially at high oscillating frequency.

Numerical Simulation Calculation of Hydroplane Direct Route Motion Based on FLUENT

2012 ◽  
Vol 569 ◽  
pp. 368-375
Author(s):  
Yu Qin ◽  
Xiao Liang ◽  
Jia Ning Zhang
Keyword(s):  
Numerical Simulation ◽  
Performance Prediction ◽  
Dynamic Pressure ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Velocity Change ◽  
Direct Route ◽  
Field Situation ◽  
Simulation Calculation

Aiming at hydrodynamic performance prediction for hydroplane motion, numerical simulation calculation for direct route motion of a hydroplane was carried out under FLUENT software platform by using VOF method and RNG k-ε model and solving Navier-Stokes equation. Evolution of ship resistance was obtained as the velocity change, and flow field situation and dynamic pressure variation of hydroplane hull bottom were reflected intuitively. By comparing the results of FLUENT calculation and ship model experiment and theoretical estimation, analyzing, especially wake current, it was verified that numerical simulation calculation of hydroplane direct route motion and hydrodynamic performance prediction based on FLUENT are feasible and precise enough.

Two-Dimensional Numerical Simulation of Vortex Shedding of Multiple Stranded Ropes

2019 ◽  
Author(s):  
Xinxin Wang ◽  
Liuyi Huang ◽  
Yanli Tang ◽  
Fenfang Zhao ◽  
Peng Sun
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Vortex Shedding ◽  
Stokes Equations ◽  
Flow Distribution ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Hydrodynamic Characteristics ◽  
Two Dimensional ◽  
Navier Stokes Equation

Abstract The stranded rope is one of the important components of the fishery aquaculture equipment. We investigate the fluid flow through two-dimensional stranded rope by direct simulation of the Navier-Stokes equations. We show that for different kinds of stranded rope structures, there are significant differences in hydrodynamic performance. This paper established a numerical model of unsteady flow past the stranded rope based on the Navier-Stokes equation and Morison formulas to study the hydrodynamic characteristics of three-stranded rope, four-stranded rope, and seven-stranded rope, respectively. The turbulence flow was simulated using Standard k-ε model and Shear-Stress Transport k-ω (SST) model. The flow distribution strongly depends on the Reynolds number, a range of 3,900 and 30,000. With increasing Reynolds number, the alternate eddy formation and shedding were repeated behind the stranded ropes. Such parameters of hydrodynamic characteristics of multiple stranded ropes were calculated as the lift and drag coefficients, and vortex shedding frequencies. The numerical simulation results presented flow performances of different cross sections (a, b, c, d) at different Reynolds numbers. However, Reynolds number has no significant impact on the Strouhal number for the same attack angle of the stranded rope.

Numerical Simulation of Muzzle Flow Field of Gun Based on CFD

2013 ◽  
Vol 291-294 ◽  
pp. 1981-1984
Author(s):  
Zhang Xia Guo ◽  
Yu Tian Pan ◽  
Yong Cun Wang ◽  
Hai Yan Zhang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Stokes Equation ◽  
Wave Structure ◽  
Flow Fields ◽  
Single Equation ◽  
Navier Stokes ◽  
Turbulent Model ◽  
Navier Stokes Equation ◽  
Numerical Simulation Result

Gunpowder was released in an instant when the pill fly out of the shell during the firing, and then formed a complicated flow fields about the muzzle when the gas expanded sharply. Using the 2 d axisymmetric Navier-Stokes equation combined with single equation turbulent model to conduct the numerical simulation of the process of gunpowder gass evacuating out of the shell without muzzle regardless of the pill’s movement. The numerical simulation result was identical with the experimental. Then simulated the evacuating process of gunpowder gass of an artillery with muzzle brake. The result showed complicated wave structure of the flow fields with the muzzle brake and analysed the influence of muzzle brake to the gass flow field distribution.

scholarly journals A note on time-fractional Navier–Stokes equation and multi-Laplace transform decomposition method

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Hassan Eltayeb ◽  
Imed Bachar ◽  
Yahya T. Abdalla
Keyword(s):  
Numerical Simulation ◽  
Approximate Solution ◽  
Decomposition Method ◽  
Adomian Decomposition Method ◽  
Approximate Solutions ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equation ◽  
Adomian Decomposition ◽  
Stokes Problems

Abstract In this study, the double Laplace Adomian decomposition method and the triple Laplace Adomian decomposition method are employed to solve one- and two-dimensional time-fractional Navier–Stokes problems, respectively. In order to examine the applicability of these methods some examples are provided. The presented results confirm that the proposed methods are very effective in the search of exact and approximate solutions for the problems. Numerical simulation is used to sketch the exact and approximate solution.

Method for Non-Dimensional Tip Leakage Flow Characterization in Radial Turbines

2018 ◽  
Author(s):  
José Ramón Serrano ◽  
Roberto Navarro ◽  
Luis Miguel García-Cuevas ◽  
Lukas Benjamin Inhestern
Keyword(s):  
Suction Side ◽  
Tip Clearance ◽  
Navier Stokes ◽  
The Novel ◽  
Tip Leakage Flow ◽  
Navier Stokes Equation ◽  
Tip Clearance Flow ◽  
Tip Leakage ◽  
Wide Range ◽  
Clearance Flow

Tip leakage loss characterization and modeling plays an important role in small size radial turbine research. The momentum of the flow passing through the tip gap is highly related with the tip leakage losses. The ratio of fluid momentum driven by the pressure gradient between suction side and pressure side and the fluid momentum caused by the shroud friction has been widely used to analyze and to compare different sized tip clearances. However, the commonly used number for building this momentum ratio lacks some variables, as the blade tip geometry data and the viscosity of the used fluid. To allow the comparison between different sized turbocharger turbine tip gaps, work has been put into finding a consistent characterization of radial tip clearance flow. Therefore, a non-dimensional number has been derived from the Navier Stokes Equation. This number can be calculated like the original ratio over the chord length. Using the results of wide range CFD data, the novel tip leakage number has been compared with the traditional and widely used ratio. Furthermore, the novel tip leakage number can be separated into three different non-dimensional factors. First, a factor dependent on the radial dimensions of the tip gap has been found. Second, a factor defined by the viscosity, the blade loading, and the tip width has been identified. Finally, a factor that defines the coupling between both flow phenomena. These factors can further be used to filter the tip gap flow, obtained by CFD, with the influence of friction driven and pressure driven momentum flow.

scholarly journals Thermo-Elastohydrodynamic Study on Textured Journal Bearing with High-Speed and High-Specific-Pressure

2019 ◽  
Vol 37 (4) ◽  
pp. 751-756 ◽  
Author(s):  
Lin Wang ◽  
Yu Zhang ◽  
Guoding Chen
Keyword(s):  
Elastic Deformation ◽  
High Speed ◽  
Journal Bearing ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Specific Pressure ◽  
Analysis Model ◽  
Navier Stokes Equation ◽  
Gear Transmission System ◽  
Load Carrying

The performance of supporting journal bearing of the star gear transmission system in the geared turbo fan engine (GTF) is analyzed. A thermal-elastohydrodynamic analysis model was developed for textured journal bearing used in high-speed and high-specific-pressure conditions. The Navier-Stokes equation, energy equation, and viscosity-temperature equation were calculated by the computational fluid dynamics method. The influence of elastic deformation on bearing thermal hydrodynamic performance was studied in detail. The results indicate that the elastic deformation has an influence on the distribution of oil temperature and oil pressure. Besides, a comparative thermo-elastohydrodynamic analysis was conducted between the textured bearing and the un-textured bearing, and the discrepancies of maximum oil pressure, load carrying capacity and the maximum oil temperature are few. However, the textured bearing has a lower elastic deformation than the un-textured bearing.

scholarly journals Aerodynamic Performances of Paper Planes

2020 ◽  
Vol 77 (1) ◽  
pp. 124-131
Author(s):  
Noor Iswadi Ismail ◽  
Zurriati Mohd Ali ◽  
Iskandar Shah Ishak ◽  
R.M. Noor ◽  
Rosniza Rabilah
Keyword(s):  
Lift Coefficient ◽  
The Other ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Aerodynamic Efficiency ◽  
Ansys Cfx ◽  
Wide Range ◽  
Aerodynamic Performances ◽  
Paper Plane ◽  
Stall Angle

Paper plane has a high potential to be upgraded as a Micro Air Vehicle (MAV). Due to its simplicity, paper plane offers easier design option compared to the biological inspired designs as shown in recent MAV development. However, researchers have underestimate and overlook the basic aerodynamic performance induced by these paper planes. This is due to its common usage as toys and wide range of paper plane design. Thus, the objective for current work is to analyse and compare the aerodynamics forces and its performance for selected paper plane design known as Glider, Wide Stunt Glider Plane and Stunt plane. A series of CFD simulations on each paper plane was executed by using ANSYS-CFX module. A steady state, incompressible flow Navier-Stokes equation (RANS) combined with Shear Stress Turbulence (SST) model were used in this works to solve flow problem over the paper planes. The analysis is mainly conducted to study and compare the lift coefficient (), drag coefficient ()and aerodynamic efficiency () performances for each paper planes. The results show that the Glider paper plane has managed to produce better performances in terms overall magnitude, stall angle, wider angle of attack (?) envelope and higher maximum lift coefficient magnitude compared to the other paper plane design. However, Glider paper plane has the least distributions by producing at least 14.3% larger magnitude compared to the other plane design at certain ? region. Instead, The Wide Stunt has promisingly produced better distribution by producing lower value compared to the other plane design. Based on performance, the Wide Stunt paper plane has produced better and maximum aerodynamic efficiency () magnitudes compared to the other design. Wide Stunt paper plane induced at least 6.4% better magnitude compared to the other paper plane design. Based on these results, it can be concluded that Wide Stunt paper plane has promising advantages which are very crucial for the paper plane especially during hovering operation, take-off and landing manoeuvre.

Sign in / Sign up

Export Citation Format

Share Document