Study of the Change of Performance of an Elastic Vertical Hydrofoil With Deformation

2014 ◽  
Author(s):  
Alexander Führing ◽  
Subha Kumpaty ◽  
Chris Stack
Keyword(s):  
Water Flow ◽  
Lift Coefficient ◽  
Flow Analysis ◽  
Turbulence Models ◽  
Flow Property ◽  
Performance Data ◽  
Cfd Analysis ◽  
Ansys Fluent ◽  
Drag Forces ◽  
Fluid Flow Analysis

In external and internal fluid flow analysis using numerical methods, most attention is paid to the properties of the flow assuming absolute rigidity of the solid bodies involved. However, this is often not the case for water flow or other fluids with high density. The pressure forces cause the geometry to deform which in turn changes the flow properties around it. Thus, a one-way and two-way Fluid-Structure Interaction (FSI) coupling is proposed and compared to a CFD analysis of a windsurfing fin in order to quantify the differences in performance data as well as the properties of the flow. This leads to information about the necessity of the use of FSI in comparison to regular CFD analysis and gives indication of the value of the enhanced results of the deformable analysis applied to water flow around an elastically deformable hydrofoil under different angles of attack. The performance data and flow property evaluation is done in ANSYS Fluent using the k-ω SST and k-ε model with a y+ of 1 and 35 respectively in order to be able to compare the behavior of both turbulence models. It is found that the overall lift coefficient in general is lower and that the flow is less turbulent because of softer transition due to the deformed geometry reducing drag forces. It is also found that the deformation of the tip of the hydrofoil leads to vertical lift forces. For the FSI analysis, one-way and two-way coupling were incorporated leading to the ability to compare results. It has been found that one-way coupling is sufficient as long as there is no stall present at any time.

An Assessment of Turbulence Models for S-Duct Diffusers With Flow Control

2013 ◽  
Author(s):  
S. P. Bhat ◽  
R. K. Sullerey
Keyword(s):  
Experimental Data ◽  
Flow Control ◽  
Turbulence Model ◽  
Flow Analysis ◽  
Turbulence Models ◽  
Experimental Results ◽  
Cfd Analysis ◽  
Duct Flow ◽  
Ansys Fluent ◽  
Sst Model

The selection of a turbulence model for a problem is not trivial and has to be done systematically after comparison of various models with experimental data. It is a well known fact that there is no such turbulence model which fits all problems ([3], [13]). The flow in S-duct diffuser is a very complex one where both separation and secondary flow coexist. Previous work by the author on CFD analysis of S-duct diffuser was done using k-ε-Standard model [1], however it has been seen that choosing other turbulence model may result in better capturing of the physics in such a problem. Also flow control, to reduce energy losses, is achieved using a technique called Zero Net Mass Flow (ZNMF), in which suction and vortex generation jets (VGJ) are combined and positioned at optimum location. A proper turbulence model has to be chosen for capturing these phenomena effectively. Extensive experimental data is available on this problem and ZNMF technique from previous work done by one of the authors which is used for validating the CFD results. Here the focus is on choosing the best turbulence model for the S-duct diffuser. Numerical (CFD) analysis is carried out using Ansys Fluent 13.0 with six turbulence models for the geometry with (ZNMF) and without (Bare duct) flow control and then compared with the experimental results. The turbulence models used are Spalart-Allmaras, three variants of k-ε – Standard, RNG and Realizable and two variants of k-ω – Standard and SST model. All the parameters of comparison are non-dimensionalized using the free stream properties, so that the results are applicable to a wider range of problems. This work is limited to incompressible flow analysis, as the experimental data is only available for low Mach number flows. Comparison of all these models clearly shows that results obtained using k-ω-SST model are very comparable to the experimental results for the bare duct (without flow control) and flow controlled duct both in terms of distribution of properties and aggregate results. Compressible flow analysis can be attempted to achieve reliable results in future with ZNMF using the best turbulence model based on this study.

scholarly journals Optimisation of Automobile Radiator by Linear and Helical Tubes

2020 ◽  
Vol 9 (5) ◽  
pp. 1172-1178
Keyword(s):  
Heat Dissipation ◽  
Cooling System ◽  
Flow Analysis ◽  
Maximum Amount ◽  
Lubricating Oil ◽  
Ansys Fluent ◽  
Helical Tube ◽  
High Level ◽  
Fluid Flow Analysis ◽  
Helical Tubes

An automobile radiator is a component of an automotive cooling system which plays a major role in transferring the heat from the engine parts to the environment through its complex working system. Heat losses through the radiator and the tailpipe add up to 58 to 62 percent of the total losses. Insufficient heat dissipation can result in the overheating of the engine, which leads to the breakdown of the lubricating oil, corrosion and metal weakening of engine parts, and significant wear between engine parts. To minimize the stress on the engine as a result of heat generation, automotive radiators must be designed to be more effective while still maintaining high level of heat transfer within components. This leads to the increased demand of power packed radiators, which can dissipate maximum amount of heat for any given space. In this paper we have designed and analyzed the performance of radiators by comparing linear tube radiator and two helical tube radiators as coolant inside radiator follows triple pass flow pattern. The modeling is done using CATIA. The fluid flow analysis is done with ANSYS FLUENT.

scholarly journals Numerical Analysis of the Aerodynamic Characteristics of NACA-4312 Airfoil

2020 ◽  
Vol 01 (02) ◽  
pp. 29-36
Author(s):  
Md Rhyhanul Islam Pranto ◽  
Mohammad Ilias Inam
Keyword(s):  
Reynolds Number ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Turbulence Models ◽  
Aerodynamic Characteristics ◽  
Numerical Results ◽  
Ansys Fluent ◽  
Coefficient Increase ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

The aim of the work is to investigate the aerodynamic characteristics such as lift coefficient, drag coefficient, pressure distribution over a surface of an airfoil of NACA-4312. A commercial software ANSYS Fluent was used for these numerical simulations to calculate the aerodynamic characteristics of 2-D NACA-4312 airfoil at different angles of attack (α) at fixed Reynolds number (Re), equal to 5×10^5 . These simulations were solved using two different turbulence models, one was the Standard k-ε model with enhanced wall treatment and other was the SST k-ω model. Numerical results demonstrate that both models can produce similar results with little deviations. It was observed that both lift and drag coefficient increase at higher angles of attack, however lift coefficient starts to reduce at α =13° which is known as stalling condition. Numerical results also show that flow separations start at rare edge when the angle of attack is higher than 13° due to the reduction of lift coefficient.

Influence of the Curvature Correction on Turbulence Models for the Prediction of the Aerodynamic Coefficients of the S809 Airfoil

2021 ◽  
Vol 43 ◽  
pp. 45-57
Author(s):  
Mohammed Nebbache ◽  
Abdelkader Youcefi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Lift Coefficient ◽  
Turbulence Models ◽  
Aerodynamic Coefficients ◽  
Ansys Fluent ◽  
Curvature Correction ◽  
Shear Stress Transport ◽  
Sst Model

Using the appropriate procedure, Computational Fluid Dynamics allows predicting many things in several fields, and especially in the field of renewable energies, which has become a promising research axis. The present study aims at highlighting the influence of the curvature correction on turbulence models for the prediction of the aerodynamic coefficients of the S809 airfoil using the Computational Fluid Dynamics code ANSYS Fluent 17.2. Three turbulence models are used: Spalart-Allmaras, Shear Stress Transport k-ω and Transition SST. Experimental results of the 1.8 m × 1.25 m low-turbulence wind tunnel at the Delft University of Technology are used in this work for comparison with the numerical results for a Reynolds number of 106. The results show that the use of the curvature correction improves the prediction of the aerodynamic coefficients for all the turbulence models used. A comparison of the three models is also made using curvature correction since it gave better results. The Transition SST model is the one that gives the best results for the lift coefficient, followed by the Shear Stress Transport kω model, and finally the Spalart-Allmaras model. For the drag coefficient, Transition SST model is the best, followed by the Spalart-Allmaras model, and finally the Shear Stress Transport kω model.

scholarly journals Numerical Investigation Aerodynamic Characteristic Installation I-65° Cylinder Type Upstream Bluffbody as Airflow Passive Control

2021 ◽  
Vol 2117 (1) ◽  
pp. 012035
Author(s):  
G Sakti ◽  
B G Cahyo ◽  
A Wulansari ◽  
A Regia ◽  
I A Dharma
Keyword(s):  
Drag Force ◽  
Passive Control ◽  
Flow Direction ◽  
Lift Coefficient ◽  
Turbulence Models ◽  
Basic Research ◽  
Reynold Number ◽  
Type I ◽  
Force Coefficient ◽  
Ansys Fluent

Abstract This report is the basic research that focuses on efforts to reduce the drag force of a cylindrical pipe by placing an interfering cylinder in the area of the incoming flow direction. The aerodynamic behavior of the central cylinder and its disturbances were modeled in 2D are discretized in laminar flow by Finite Volume Methode using Ansys Fluent®. Efforts to reduce the drag force are carried out with the main cylinder diameter D=60 mm and the interfering cylinder type I-65° with diameter d/D = 0.125. The distance between the center points of the two cylinders being s/D=1,4 and Reynold number Re = 5.3 x 10 4 at a speed of U∞=14 m/s. Numerical simulation using variations of turbulent models k-epsilon (2eq), k-omega (2eq), and transition k-kl-omega (3eq). The results of this research can show better aerodynamic performance. Placing the cylinder I-65° in tandem can reduce the average drag force coefficient by 68% at 700-800 timesteps. In contrast, the average lift coefficient decreased by 13% at the same timestep. The results were obtained with transition k-kl-omega (3eq) turbulence models that have been validated and able to approach the referenced experimental data.

Industry-University Collaborative Project on Numerical Predictions of Cavitating Flows in Hydraulic Machinery: Part 1—Benchmark Test on Cavitating Hydrofoils

2011 ◽  
Author(s):  
Chisachi Kato
Keyword(s):  
Loading Condition ◽  
Lift Coefficient ◽  
Turbulence Models ◽  
Breakdown Point ◽  
Computational Grids ◽  
Navier Stokes ◽  
Cavitating Flows ◽  
Ansys Fluent ◽  
Collaborative Project ◽  
Numerical Predictions

Through an industry-university collaborative project, extensive benchmark studies have been made for numerical prediction of cavitating flows around two-dimensional Hydrofoils: Clark-Y 11.7% and NACA0015. The emphases are placed on the ability of present cavitation models to predict the breakdown characteristics for these hydrofoils. The benchmarking was done for a light and a moderate loading condition of these hydrofoils at a chord-based Reynolds number in the order of 106. Four commercial CFD flow solvers, ANSYS CFX, ANSYS Fluent, and STAR-CCM+, and SCRYU/Tetra, along with four open-source or in-house flow solvers in universities participated in this benchmark. All the cavitation models, except one, implemented in these flow solvers are based on an assumption of homogenous media of one fluid, for which inception, growth, decay and destruction of cavitation are expressed by density change of the mixture fluid composed of liquid and gas phases. They differ with each other in how they determine the mixture fluid density and can be categorized into of barotropic type or of source-sink type. Despites these differences in the cavitation models themselves and differences in the Navier-Stokes solvers, turbulence models and computational grids, the results of the benchmark show a consistent trend of discrepancy between the predicted and measured breakdown characteristics. Namely, none of the cavitation models is able to predict sudden drop of the lift coefficient near the breakdown point confirmed in the measured characteristics. The lift coefficients predicted by all the cavitation models show a gradual decrease with decreasing cavitation number. This discrepancy between the predicted and measured breakdown characteristics is most prominent at the higher loading condition for NACA0015. But, it is consistently confirmed for the other cases investigated in this benchmark. The difference seems to be the results of under prediction of the cavity length, which probably comes from an intrinsic limitation associated with a cavitation model based on an assumption of homogeneous media of one fluid.

Experimental and Computational Fluid Dynamics (CFD) Study of Glazed Three Dimensional PV/T Solar Panel with Air Cooling

2015 ◽  
Vol 787 ◽  
pp. 102-106
Author(s):  
R. Senthil Kumar ◽  
N. Puja Priyadharshini ◽  
Elumalai Natarajan
Keyword(s):  
Fluid Dynamic ◽  
Geometric Model ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Solar Panel ◽  
Air Cooling ◽  
Outlet Temperature ◽  
Ansys Fluent ◽  
The Difference ◽  
Fluid Flow Analysis

The thermal performances of photovoltaic thermal (PV/T) flat plate panel were determined under 500–1000 W/m2 solar radiation levels. In the present work, fluid flow analysis and temperature distribution on solar panel has been carried out by experimental method and computational fluid dynamic (CFD) technique. The experiments have been carried out on clear days during the month April 2014. The geometric model for CFD analysis is generated using Solidworks. Mesh generation is accomplished by ANSYS Meshing Software. Physics setup, computation and post processing are accomplished by ANSYS FLUENT. The experimentally measured temperatures are compared to the temperatures determined by the CFD model and found to be in good agreement. It is also found that the difference between the experimental and CFD simulated outlet temperature differ only by less than 3.5°C.

Sign in / Sign up

Export Citation Format

Share Document