scholarly journals Estimation of car air resistance by CFD method

2014 ◽  
Vol 36 (3) ◽  
pp. 235-244 ◽  
Author(s):  
Phan Anh Tuan ◽  
Vu Duy Quang

Total car resistance is including rolling resistance and air resistance. Rolling resistance comes from car tires when it rolls over the roads with car weight. Air resistance comes from the body when it moves in the air with car body surface area. The air resistance of a car depends upon its shape. The bigger the surface area of a car body, the more air molecules the car will hit and so the larger the air resistance. This paper will mention to estimation of car air resistance by computational fluid dynamics (CFD) method. A 3D car body has used for simulation in ANSYS FLUENT CFD software. The k-\(\varepsilon\) turbulence model and segregated implicit solver was used to perform computation in this study.

2012 ◽  
Vol 220-223 ◽  
pp. 1698-1702
Author(s):  
Jian Chen ◽  
Zhu Ming Su ◽  
Qi Zhou ◽  
Jian Ping Shu

A novel hydraulic rotary high speed on/off valve is investigated. The function of the outlet turbine and the effect on revolution speed of valve spool are analyzed. The inner fluid flow condition under full open case of the on/off valve is simulated using computational fluid dynamics(CFD) method based on Ansys/Fluent and velocity and pressure profiles of fluid inside valve are obtained. Suggestions on optimizing the geometry of valve to decrease transition losses are given.


2021 ◽  
Vol 11 (5) ◽  
pp. 2200
Author(s):  
Sungchan Hong ◽  
Takeshi Asai

In cycling, air resistance corresponds to 90% of the resistance on the bicycle and cyclist and 70% of this is applied to the body of the cyclist. Despite research on postures that could reduce air resistance, few studies have been conducted on full-body cycling suits. As the aerodynamics of the surface shape of clothing fabric are still unclear, the airflow around cyclists and air resistance were examined using a computational fluid dynamics (CFD) method and wind tunnel experiment. Specifically, in this study, we focused on how different surface shapes of cycling suit fabrics affect air resistance. CFD results indicate that air resistance during a race was high at the head, arms and legs of the cyclist. In the wind tunnel experiment, a cylinder model resembling the arms was used to compare the aerodynamic forces of various fabrics and the results showed that air resistance changed according to the fabric surface shape. Moreover, by changing the fabric shape of the arms of the cycling suits, reduction of air resistance by up to 8% is achievable. These results suggest that offering the most appropriate suit type to each cyclist, considering race conditions, can contribute to further improvement in their performance.


Author(s):  
D. Dupleac

The paper overviews the analytical studies performed at Politehnica University of Bucharest on the analysis of late phase severe accident phenomena in a Canada Deuterium Uranium (CANDU) plant. The calculations start from a dry debris bed at the bottom of calandria vessel. Both SCDAPSIM/RELAP code and ansys-fluent computational fluid dynamics (CFD) code are used. Parametric studies are performed in order to quantify the effect of several identified sources of uncertainty on calandria vessel failure: metallic fraction of zirconium inside the debris, containment pressure, timing of water depletion inside calandria vessel, steam circulation in calandria vessel above debris bed, debris temperature at moment of water depletion inside calandria vessel, calandria vault nodalization, and the gap heat transfer coefficient.


2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Sulistiya Sulistiya ◽  
Alief Sadlie Kasman

AbstractNumerical simulation using Computational Fluid Dynamics (CFD) method is one way of predicting airflow characteristics on the model. This method is widely used because it is relatively inexpensive and faster in getting desired results compared with performing direct testing. The correctness of a computational simulation output is highly dependent on the input and how it was processed. In this paper, simulation is done on Onera M6 Wing, to investigate the effect of a turbulence model’s application on the accuracy of the computational result. The choice of Onera M6 Wing as a simulation’s model is due to its extensive database of testing results from various wind tunnels in the world. Among Turbulence models used are Spalart-Allmaras, K-Epsilon, K-Omega, and SST.Keywords: CFD, fluent, Model, Turbulence, Onera M6, Spalart-Allmaras, K-Epsilon, K-Omega, SST.AbstraksSimulasi numerik dengan menggunakan metode Computational Fluid Dynamics (CFD) merupakan salah satu cara untuk memprediksi karakteristik suatu aliran udara yang terjadi pada model. Metode ini banyak digunakan karena sifatnya yang relatif murah dan cepat untuk mendapatkan hasil dibandingkan dengan melakukan pengujian langsung. Benar tidak hasil sebuah simulasi komputasi sangat tergantung pada inputan yang diberikan serta cara memproses data inputan tersebut. Pada tulisan ini dilakukan simulasi dengan menggunakan sayap onera M6 dengan tujuan untuk mengetahui pengaruh penggunaan model turbulensi terhadap keakuratan hasil komputasi. Pilihan sayap onera M6 sebagai model simulasi dikarenakan model tersebut sudah memiliki database hasil pengujian yang cukup lengkap dan sudah divalidasi dari berbagai terowongan angin di dunia. Model turbulensi yang digunakan diantaranya Spalart-Allmaras, K-Epsilon, K-Omega dan SST.Kata Kunci : CFD, fluent, Model, Turbulensi, Onera M6, Spalart-Allmaras, K-Epsilon, K-Omega, SST.


2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Benarfaoui Arfaoui ◽  
Mohamed Taher Bouzaher ◽  
Belhi Guerira ◽  
Charaf-Eddine Bensaci

Abstract This study investigates the energy extraction mechanism by means of swing arm turbine. The swing arm turbines have a particular motion pattern. The pure translation motion in the conventional flapping turbine changes based on the swing arm rotation. The laminar flow around a NACA0015 is resolved using computational fluid dynamics (CFD) method. The turbine blades are equipped with an oscillating gurney flap for trying to boost the system efficiency. The connected gurney flap oscillates with a given pitching angle. A user-defined function and the sliding dynamic mesh technique available in ansys fluent version 15 are used to adjust both the blade and the flap positions during the turbine flapping cycle. The effects of the swing factor and the flap length on the system performance are provided. It is shown that the suggested strategy of control is able to alter the pressure distribution during both the up stroke and down stroke phases, which changes the blade aerodynamic forces during all the flapping cycle portions and therefore improving the turbine efficiency.


Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3350 ◽  
Author(s):  
Guoping Huang ◽  
Xin Xiang ◽  
Chen Xia ◽  
Weiyu Lu ◽  
Lei Li

The reduction in specific fuel consumption (SFC) is crucial for small/mid-size cost-controllable aircraft, which is very conducive to reducing cost and carbon dioxide emissions. To decrease the SFC, increasing the bypass ratio (BPR) is an important way. Conventional high-BPR engines have several limitations, especially the conflicting spool-speed requirements of a fan and a low-pressure turbine. This research proposes an air-driven fan with a tip turbine (ADFTT) as a potential device for a high-bypass propulsion system. Moreover, a possible application of this ADFTT is introduced. Thermodynamic analysis results show that an ADFTT can improve thrust from a prototype turbofan. As a demonstration, we selected a typical small-thrust turbofan as the prototype and applied the ADFTT concept to improve this model. Three-dimensional flow fields were numerically simulated through a Reynolds averaged Navier-Stokes (RANS)-based computational fluid dynamics (CFD) method. The performance of this ADFTT has the possibility of amplifying the BPR more than four times and increasing the thrust by approximately 84% in comparison with the prototype turbofan.


2018 ◽  
Vol 178 ◽  
pp. 05014 ◽  
Author(s):  
Andrzej Baier ◽  
Łukasz Grabowski ◽  
Łukasz Stebel ◽  
Mateusz Komander ◽  
Przemysław Konopka ◽  
...  

Numerical analysis of drag values of an electric race car's body. Silesian Greenpower is a student organization specializing in electric race car design. One of the most important issues during the design is reducing the vehicle drag to minimum and is done, mainly, by designing a streamline car body. The aim of this work was to design two electric cars bodies with different shape in Siemens NX CAD software, next a finite elements mesh was created and implemented into the ANSYS Workbench 16.1 software. Afterwards an aerodynamic analysis was carried out, using the finite element method (FEM). Simulations and calculations have been performed in ANSYS Fluent: CFD Simulation software. Computer simulation allowed to visualize the distribution of air pressure on and around car, the air velocity distribution around the car and aerodynamics streamline trajectory. The results of analysis were used to determine the drag values of electric car and determine points of the highest drag. In conclusion car body representing lower drag was appointed. The work includes theoretical introduction, containing information about finite element method, ANSYS and Siemens NX software and also basic aerodynamics laws.


2012 ◽  
Vol 516-517 ◽  
pp. 1074-1077
Author(s):  
Xue Feng Zhao ◽  
Li Min He ◽  
Li Xin Zhao ◽  
Sheng Zhong ◽  
Yang Wang

Based on computational fluid dynamics (CFD) method, applying FLUENT software, taking a de-oil hydrocyclone as an original structure, the effect of porous overflow pipe on the performance and pressure characteristics is analyzed. Effect of overflow-pipe length and diameter of the porous overflow-pipe (POP) hydrocyclone is studied. It is found that the extension of overflow-pipe length can play a coalescent role; the new type hydrocyclone can increase oil content around overflow outlet so as to be beneficial for the enhancement of separation effect.


2010 ◽  
Vol 160-162 ◽  
pp. 280-286
Author(s):  
Ri Chao Liu ◽  
Zhong Hua Tang ◽  
Wei Yang Qi

This paper adopted computational fluid dynamics (CFD) method, used k-ε RNG turbulence model-closed control differential equations for numerical simulation. Through numerical simulation and analysis of wind environment in a middle school campus, the round wind field under dominant wind direction was got in the summer and winter. According to the results of velocity field and pressure field, analysis the wind environment, compared the influence of wind direction and surrounding buildings space to the natural ventilation, provided guidance introduce for the layout of the school.


2013 ◽  
Vol 61 (1) ◽  
pp. 155-160 ◽  
Author(s):  
G. Sztarbała

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


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