Validation of CFD Predictions of the Hull Resistance and the Wave System of a Catamaran

2012 ◽  
Author(s):  
Alexandre T. P. Alho
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Design Process ◽  
Scale Effects ◽  
Wave System ◽  
Computational Fluid Dynamics Cfd ◽  
Resistance Prediction ◽  
Low Costs

In response to the need for better designs in less time and at low costs, computational fluid dynamics (CFD) is becoming an integral part of the vessel’s design process. Recent studies have shown that CFD techniques can be used with relative success for the problem of ship resistance prediction. This paper reports on the simulation of the flow around a typical catamaran hull by means of CFD computations. The numerical model used in the simulations was developed in full scale with the experimental model in order to eliminate any source of scale effects. The paper presents a discussion on grid configuration and an analysis of the performance of the numerical model in describing the characteristics of the in-between hulls flow. The results obtained were validated against experimental data.

scholarly journals Modelling of working processes of non-contact oil free vacuum pumps by computational fluid dynamics (CFD) methods

2021 ◽  
Vol 2059 (1) ◽  
pp. 012003
Author(s):  
A Burmistrov ◽  
A Raykov ◽  
S Salikeev ◽  
E Kapustin
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Mathematical Models ◽  
Cfd Models ◽  
Ansys Cfx ◽  
Sst Turbulence Model ◽  
Computational Fluid Dynamics Cfd ◽  
Dynamic Meshing ◽  
Comparison With Experimental Data

Abstract Numerical mathematical models of non-contact oil free scroll, Roots and screw vacuum pumps are developed. Modelling was carried out with the help of software CFD ANSYS-CFX and program TwinMesh for dynamic meshing. Pumping characteristics of non-contact pumps in viscous flow with the help of SST-turbulence model were calculated for varying rotors profiles, clearances, and rotating speeds. Comparison with experimental data verified adequacy of developed CFD models.

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.

scholarly journals Numerical Investigation on the Scale Effect of a Stepped Planing Hull

2019 ◽  
Vol 7 (11) ◽  
pp. 392 ◽  
Author(s):  
Lei Du ◽  
Zhuang Lin ◽  
Yi Jiang ◽  
Ping Li ◽  
Yue Dong
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Scale Effect ◽  
Scale Effects ◽  
Calculated Data ◽  
Oscillation Period ◽  
Friction Resistance ◽  
Tank Test ◽  
Computational Fluid Dynamics Cfd ◽  
Resistance Coefficients

This article discusses the scale effects on a planing boat, utilizing the computational fluid dynamics method. The simulation is compared with a tank test for verification and validation. The planing boat sails use both aerodynamics and hydrodynamics. Studying the performances and wave patterns of different dimensions of the models is the best way to investigate the scale effect without using experimental data. The resistance is discussed in two parts, namely residuary resistance and friction resistance, and is compared to the calculated data using the international towing tank conference (ITTC) formula. The computational fluid dynamics (CFD) calculations of the model are increased by 4.77% on average, and the boat computations are also increased by 3.57%. The computation shows the scale effect in detail. The residuary resistance coefficients at different scales are approximately equal, and the friction resistance coefficients show the scale effect. The scale effect for longitudinal steadiness is also captured for the period of the porpoising behavior. The rational for the full-scaled boat oscillation period and the model is the root of the scales.

Inlet Losses in Counterflow Wet-Cooling Towers

2001 ◽  
Vol 123 (2) ◽  
pp. 460-464 ◽  
Author(s):  
E. de Villiers ◽  
D. G. Kro¨ger
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Loss Coefficient ◽  
Cooling Towers ◽  
Empirical Correlations ◽  
Dependent Variables ◽  
Loss Coefficients

The inlet loss coefficients for dry, isotropically packed, circular and rectangular counterflow cooling towers are determined experimentally and empirical correlations are formulated to fit this data. Computational fluid dynamics is used to investigate the dependence of the inlet loss coefficient on the rain zone characteristics. The rain zone generally dampens the inlet loss, but the coupling is indirect and involves a large number of dependent variables. The numerical model is validated by means of experimental data for dry towers and it is found that the degree of accuracy achieved for circular towers exceeds that for rectangular towers. Consequently, the correlation derived to predict this occurrence for circular towers can be applied more confidently than its rectangular counterpart.

scholarly journals An estimation of conditions inside construction works during a fire with the use of Computational Fluid Dynamics

2013 ◽  
Vol 61 (1) ◽  
pp. 155-160 ◽  
Author(s):  
G. Sztarbała
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Process ◽  
Fire Safety ◽  
Internal Environment ◽  
Preliminary Stage ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Construction Works

Abstract The aim of this paper is to present the application of Computational Fluid Dynamics (CFD) to the assessment of conditions inside construction works during a fire. The CFD method is now commonly used to support the design process of fire safety in construction works. This method is very useful at the preliminary stage of design because it is possible to check the internal environment during a fire and evaluate whether requirements of fire safety are met

A Study of Aerodynamics Force Evaluation of Horizontal Axis Wind Turbine (HAWT) Blade Using 2D and 3D Comparison

2015 ◽  
Author(s):  
Nazia Binte Munir ◽  
Kyoungsoo Lee ◽  
Ziaul Huque ◽  
Raghava R. Kommalapati
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Blade Surface ◽  
Aerodynamic Forces ◽  
Horizontal Axis Wind Turbine ◽  
Computational Fluid Dynamics Cfd ◽  
Experimental Values ◽  
Nrel Phase Vi

The main purpose of the paper is to use Computational Fluid Dynamics (CFD) in 3-D analysis of aerodynamic forces of a Horizontal Axis Wind Turbine (HAWT) blade and compare the 3-D results with the 2-D experimental results. The National Renewable Energy Laboratory (NREL) Phase VI wind blade profile is used as a model for the analysis. The results are compared with the experimental data obtained by NREL at NASA Ames Research Center for the NREL Phase VI wind turbine blade. The aerodynamic forces are evaluated using 3-D Computational Fluid Dynamics (CFD) simulation. The commercial ANSYS CFX and parameterized 3-D CAD model of NREL Phase VI are used for the analysis. The Shear Stress Transport (SST) Gamma-Theta turbulence model and 0-degree yaw angle condition are adopted for CFD analysis. For the case study seven varying wind speeds (5 m/s, 7 m/s, 10 m/s, 13 m/s, 15 m/s, 20 m/s, 25 m/s) with constant blade rotational speed (72 rpm) are considered. To evaluate the 3-D aerodynamic effect sectional pressure coefficient (Cp) and integrated forces about primary axis such as normal, tangential, thrust and torque are evaluated for each of the seven wind speed cases and compared with the NREL experimental values. The numerical difference of values on wind blade surface between this study and 3-D results of NREL wind tunnel test are found negligible. The paper represents an important comparison between the 3-D lift & drag coefficient with the NREL 2-D experimental data. The results shows that though the current study is in good agreement with NREL 3-D experimental values there is large deviation between the NREL 2-D experimental data and current 3-D study which suggests that in case of 3-D analysis of aerodynamic force of blade surface it is better to use NREL 3-D values instead of 2-D experimental values.

Verification and validation of a computational fluid dynamics (CFD) model for air entrainment at spillway aerators

2009 ◽  
Vol 36 (5) ◽  
pp. 826-836 ◽  
Author(s):  
M. Cihan Aydin ◽  
Mualla Ozturk
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Physical Model ◽  
Scale Effects ◽  
Air Entrainment ◽  
Cfd Modeling ◽  
Policy Statement ◽  
Numerical Verification ◽  
Empirical Equations ◽  
Computational Fluid Dynamics Cfd

The results of computational fluid dynamics (CFD) modeling obtained by using FLUENT software with respect to the air entrainment at spillway aerators are compared with data from a physical model study, as well as the results of some empirical equations and prototype observations presented by other investigators. The air-entrainment rates obtained from the CFD analyses are in reasonable agreement with the prototype data and the values calculated from empirical equations, and are better than the physical model data, which include considerable scale effects. The numerical verification procedure in this study is based on the American Society of Mechanical Engineers (ASME) editorial policy statement, which provides a framework for CFD uncertainty analysis. Thus, validation of the CFD is discussed within the scope of this study.

Numerical Investigation of Dusts Removal from Tramway Surface by Street Vacuum Sweeper

2011 ◽  
Vol 236-238 ◽  
pp. 1619-1622 ◽  
Author(s):  
Bo Fu Wu ◽  
Jin Lai Men ◽  
Jie Chen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Pressure Drop ◽  
Removal Efficiency ◽  
Pressure Drops ◽  
Operational Safety ◽  
Airflow Field ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

In order to enhance the operational safety of tram vehicle and reduce the wear of guide wheels mounted on the vehicle, it is necessary to remove particles such as dusts and silts from tramway surface. The aim of this paper is to evaluate the effectiveness of street vacuum sweeper for sucking up dusts from tramway surface. A numerical model was developed based on dusts removal process. Under different pressure drops across the pickup head of the street vacuum sweeper, the flow field and dusts removal efficiency were analyzed with computational fluid dynamics (CFD) method. The numerical results show that a higher pressure drop can improve the airflow field in the pickup head and results in higher dusts removal efficiency, but higher pressure drop definitely need more energy. Therefore, a balance should be taken into consideration.

scholarly journals Computational Aerodynamics: Solvers and Shape Optimization

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Luigi Martinelli ◽  
Antony Jameson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shape Optimization ◽  
Design Process ◽  
Optimization Techniques ◽  
Personal Account ◽  
Computational Aerodynamics ◽  
Computational Fluid Dynamics Cfd

Aeronautics, and in particular aerodynamics, has been one of the main technological drivers for the development of computational fluid dynamics (CFD). This paper presents a personal account of the main advances in the development of solvers and shape optimization techniques, which have contributed to make CFD an essential part of the design process of modern aircraft.

CFD Simulation and Computation of Pressure Loss of Resistance Muffler

2013 ◽  
Vol 694-697 ◽  
pp. 307-311
Author(s):  
Jia Wei Ren ◽  
Qin Yu Jiang ◽  
Zhen Wang
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Pressure Loss ◽  
Cfd Simulation ◽  
Internal Flow ◽  
Simulation Algorithm ◽  
Air Velocity ◽  
Loss Of Resistance ◽  
Computational Fluid Dynamics Cfd

Computational fluid dynamics (CFD) software was used to simulate the internal flow field of an example muffler, and compared the results with the experimental data, verifying the reliability of the simulation algorithm. On this basis, changed the example muffler structure, researched the pressure loss of muffler which was influenced by the insert duct, the position of the baffle and the inlet air velocity. The corresponding regularities have been obtained with the results of computations, which provide a basis for the design of the muffler.

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