scholarly journals Analysis of drag and lift forces for a sedan car using a rear lip spoiler

2020 ◽  
pp. 23-31
Author(s):  
Juan Gregorio Hortelano-Capetillo ◽  
J. Merced Martínez-Vázquez ◽  
José Luis Zúñiga-Cerroblanco ◽  
Gabriel Rodriguez-Ortiz
Keyword(s):  
Flow Simulation ◽  
Simulation Software ◽  
Drag And Lift Coefficients ◽  
Drag Forces ◽  
Lift Forces ◽  
Drag And Lift

In this research, aerodynamic tests were carried out using Solidworks Flow Simulation software on a Sedan-type car, implementing different sizes of lip-type spoilers at the rear to obtain the results of the drag and lift coefficients produced by movement. of the air regardless of the design at the rear of the car and analyze if there was improvement in aerodynamics. Analyzing the results, it is obtained that the aerodynamics of the car is improved when a lip-type spoiler is fitted, the lift forces were reduced, whereas the drag forces remained constant for all the different designs.

scholarly journals Análisis aerodinámico en CFD de los alerones en automóviles convencionales

2020 ◽  
pp. 1-12
Author(s):  
Juan Gregorio HORTELANO-CAPETILLO ◽  
J. Merced MARTÍNEZ-VÁZQUEZ ◽  
Gabriel RODRIGUEZ-ORTIZ
Keyword(s):  
Flow Simulation ◽  
Simulation Software ◽  
Drag And Lift Coefficients ◽  
Lift Forces ◽  
Drag And Lift

In the present study aerodynamic tests were performed by using Solidworks Flow Simulation software (CFD) in 2 different designs of conventional cars, implementing a spoiler in the back of the car to reduce the drag and lift coefficients that occur through the movement of the air regardless of the design in the back of the car and improve aerodynamics. Analyzing the results it is obtained that the aerodynamics of the car is improved when a spoiler is placed to reduce the drag and lift forces.

Prediction of drag and lift forces of a high-speed vessel at full scale by CFD-based GEOSIM method

2022 ◽  
pp. 147509022110707
Author(s):  
Ugur Can ◽  
Sakir Bal
Keyword(s):  
High Speed ◽  
Full Scale ◽  
Navier Stokes ◽  
Drag Forces ◽  
Fluid Body ◽  
Unsteady Rans ◽  
Lift Forces ◽  
Drag And Lift ◽  
Lift And Drag ◽  
Model Family

In this study, it was aimed to obtain an accurate extrapolation method to compute lift and drag forces of high-speed vessels at full-scale by using CFD (Computational Fluid Dynamics) based GEOSIM (GEOmetrically SIMilar) method which is valid for both fully planing and semi-planing regimes. Athena R/V 5365 bare hull form with a skeg which is a semi-displacement type of high-speed vessel was selected with a model family for hydrodynamic analyses under captive and free to sinkage/trim conditions. Total drag and lift forces have been computed for a generated GEOSIM family of this form at three different model scales and full-scale for Fr = 0.8 by an unsteady RANS (Reynolds Averaged Navier–Stokes) solver. k–ε turbulence model was used to simulate the turbulent flow around the hulls, and both DFBI (Dynamic Fluid Body Interaction) and overset mesh technique were carried out to model the heave and pitch motions under free to sinkage/trim condition. The computational results of the model family were used to get “drag-lift ratio curve” for Athena hull at a fixed Fr number and so the corresponding results at full scale were predicted by extrapolating those of model scales in the form of a non-dimensional ratios of drag-lift forces. Then the extrapolated full-scale results calculated by modified GEOSIM method were compared with those of full-scale CFD and obtained by Froude extrapolation technique. The modified GEOSIM method has been found to be successful to compute the main forces (lift and drag) acting on high-speed vessels as a single coefficient at full scale. The method also works accurately both under fully and semi-planing conditions.

scholarly journals Drag and lift force analysis for the cybertruck Tesla vehicle

2021 ◽  
pp. 9-16
Author(s):  
J. Gregorio Hortelano-Capetillo ◽  
J. Merced Martínez-Vázquez ◽  
Esperanza Baños-Lopez ◽  
J. Arturo Alfaro-Ayala
Keyword(s):  
Stokes Equations ◽  
Flow Simulation ◽  
Simulation Software ◽  
Three Dimensions ◽  
Navier Stokes ◽  
Force Analysis ◽  
Navier Stokes Equations ◽  
Continuity Equations ◽  
Drag And Lift ◽  
Volume Method

In this research, aerodynamic tests were carried out at different speeds by using Solidworks Flow Simulation software in the Tesla Cybertruck vehicle, knowing the results of the drag and lift coefficients. The method was selected in three dimensions, the continuity equations and the Navier-Stokes equations that were solved by the finite volume method, the k-ɛ model was chosen to close the amounts of turbulence.

scholarly journals Correlation Between Vibration Excitation Forces and the Dynamic Characteristics of Two-Phase Flow in a Rotated Triangular Tube Bundle

2006 ◽  
Author(s):  
C. Zhang ◽  
M. J. Pettigrew ◽  
N. W. Mureithi
Keyword(s):  
Void Fraction ◽  
Cross Flow ◽  
Main Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Drag Forces ◽  
Vibration Excitation ◽  
Tube Bundles ◽  
Lift Forces ◽  
Drag And Lift

Two-phase cross flow exists in many shell-and-tube heat exchangers. Flow-induced vibration excitation forces can cause tube motion that will result in long-term fretting-wear or fatigue. Detailed flow and vibration excitation force measurements in tube bundles subjected to two-phase cross flow are required to understand the underlying vibration excitation mechanisms. Some of this work has already been done. The distributions of both void fraction and bubble velocity in rotated-triangular tube bundles were obtained. Somewhat unexpected but significant quasi-periodic forces in both the drag and lift directions were measured. The present work aims at understanding the nature of such unexpected drag and lift quasi-periodic forces. An experimental program was undertaken with a rotated-triangular array of cylinders subjected to air/water flow to simulate two-phase mixtures. Fiber-optic probes were developed to measure local void fraction. Both the dynamic lift and drag forces were measured with a strain gage instrumented cylinder. The investigation showed that the quasi-periodic drag and lift forces are generated by different mechanisms that have not been observed so far. The quasi-periodic drag forces appear related to the momentum flux fluctuations in the main flow path between the cylinders. The quasi-periodic lift forces, on the other hand, are mostly correlated to oscillations in the wake of the cylinders. The relationships between the lift or drag forces and the dynamic characteristics of two-phase flow are established through fluid mechanics momentum equations. The quasi-periodic lift forces are related to local void fraction measurements in the unsteady wake area between upstream and downstream cylinders. The quasi-periodic drag forces correlate well with similar measurements in the main flow stream between cylinders.

Influence of the Draft Condition on Vortex-Induced Motions of a Semi-Submersible Platform With Four Square Columns

2016 ◽  
Author(s):  
Mingyue Liu ◽  
Longfei Xiao ◽  
Haining Lu ◽  
Jun Li ◽  
Xiaochuan Yu
Keyword(s):  
Column Height ◽  
Transverse Motion ◽  
Experimental Investigations ◽  
Drag Forces ◽  
Draft Model ◽  
Restoring Forces ◽  
Lift Forces ◽  
Four Square ◽  
Drag And Lift ◽  
Motion Amplitude

The vortex-induced motions (VIM) phenomenon of semi-submersibles has drawn increasing attention with the development (mainly increase of column size) of new semi-submersibles. Due to the elongated submerged columns and the enlarged projected area to current, deep-draft semi-submersible platforms are susceptible to higher in-line drag forces and transverse vortex-induced lift forces, resulting in considerable horizontal motions in a current environment. In order to check the influence of draft conditions on VIM of the semi-submersible platform with four square columns, experimental investigations with five draft ratios varying from 0.87 to 1.90 were carried out in a towing tank. The 6-degree-of-freedom (6-DOF) motions of the model were recorded by the motion acquisition system, in synchronisation with restoring forces provided by four load cells, one for each horizontal mooring spring. This paper discusses the dynamic behavior of a semi-submersible platform in five different draft conditions, including coupled motions at the water surface plane, drag and lift forces, and spectral analysis. It is shown that the largest transverse amplitudes are around 75% of the column width in the range of 6.0 ≤ Ur ≤ 8.0 for the deep-draft semi-submersible (H/L = 1.90). With 50% of the immerged column height of the deep-draft model, a 30% decrease in the transverse motion amplitude can be seen. Furthermore, the effects of the draft condition on yaw responses and current loads are also addressed.

Correlation Between Vibration Excitation Forces and the Dynamic Characteristics of Two-Phase Cross Flow in a Rotated-Triangular Tube Bundle

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
C. Zhang ◽  
M. J. Pettigrew ◽  
N. W. Mureithi
Keyword(s):  
Void Fraction ◽  
Cross Flow ◽  
Main Flow ◽  
Experimental Program ◽  
Two Phase ◽  
Drag Forces ◽  
Vibration Excitation ◽  
Tube Bundles ◽  
Lift Forces ◽  
Drag And Lift

Two-phase cross flow exists in many shell-and-tube heat exchangers. Flow-induced vibration excitation forces can cause tube motion that will result in long-term fretting wear or fatigue. Detailed flow and vibration excitation force measurements in tube bundles subjected to two-phase cross flow are required to understand the underlying vibration excitation mechanisms. Some of this work has already been done. The distributions of both void fraction and bubble velocity in rotated-triangular tube bundles were obtained. Somewhat unexpected but significant quasiperiodic forces in both the drag and lift directions were measured. The present work aims at understanding the nature of such unexpected drag and lift quasiperiodic forces. An experimental program was undertaken with a rotated-triangular array of cylinders subjected to air/water flow to simulate two-phase mixtures. Fiber-optic probes were developed to measure local void fraction. Both the dynamic lift and drag forces were measured with a strain gage instrumented cylinder. The investigation showed that the quasiperiodic drag and lift forces are generated by different mechanisms that have not been previously observed. The quasiperiodic drag forces appear related to the momentum flux fluctuations in the main flow path between the cylinders. The quasiperiodic lift forces, on the other hand, are mostly correlated to oscillations in the wake of the cylinders. The quasiperiodic lift forces are related to local void fraction measurements in the unsteady wake area between upstream and downstream cylinders. The quasiperiodic drag forces correlate well with similar measurements in the main flow stream between cylinders.

Comparative Analysis of Thrust Production for Distinct Arm-Pull Styles in Competitive Swimming

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Alfred von Loebbecke ◽  
Rajat Mittal
Keyword(s):  
Computer Animation ◽  
Underwater Video ◽  
Front Crawl ◽  
Competitive Swimming ◽  
Video Footage ◽  
Drag Forces ◽  
Computational Fluid Dynamics Cfd ◽  
Lift Forces ◽  
Drag And Lift ◽  
Thrust Production

A computational fluid dynamics (CFD) based analysis of the propulsive forces generated by two distinct styles of arm-pulls in front-crawl as well as backstroke is presented in this Technical Brief. Realistic models of the arm pulling through water are created by combining underwater video footage and laser-scans of an arm with computer animation. The contributions of drag and lift forces on the arm to thrust are computed from CFD, and it is found that lift forces provide a dominant contribution to thrust for all the arm-pull styles examined. However, contrary to accepted notions in swimming, pronounced sculling (lateral motion) not only does not increase the contribution of lift forces on the hand to overall thrust, it decreases the contribution of drag forces to thrust. Consequently, pronounced sculling seems to reduce the effectiveness of the arm-pull.

Computer Simulation of an Engine Environmental Control System

2013 ◽  
Vol 850-851 ◽  
pp. 355-358
Author(s):  
Dong Du
Keyword(s):  
Control System ◽  
Distribution System ◽  
Environmental Control ◽  
Cooling System ◽  
Flow Simulation ◽  
Aircraft Engine ◽  
Simulation Software ◽  
Temperature Decrease ◽  
Environmental System ◽  
Passenger Aircraft

This paper describes the use of Fluid Flow Simulation Software to model a passenger aircraft engine environmental control system. The analysis simulates the cooling pack and the engine distribution system in a single model.The engine environmental system is very important for engine working efficiently. Using AMEsim software to simulate the cooling system can make it easily and clearly. The influence of the heat component and the fan operating is studied also. Through the analysis of the cooling system, we know that with the help of fan, the system can get additional air in the radiator and make the temperature decrease consequently.

Simplified Aerodynamic Loading Model for Non-Production Conditions for Floating Wind Systems Design

2021 ◽  
Author(s):  
Armando Alexandre ◽  
Raffaello Antonutti ◽  
Theo Gentils ◽  
Laurent Mutricy ◽  
Pierre Weyne
Keyword(s):  
Wind Speed ◽  
Coupled Model ◽  
Systems Design ◽  
Simplified Model ◽  
Aerodynamic Loads ◽  
Drag And Lift Coefficients ◽  
Aerodynamic Loading ◽  
Yaw Bearing ◽  
Drag And Lift ◽  
Turbine Model

Abstract Floating wind is now entering a commercial-stage, and there are a significant number of commercial projects in countries like France, Japan, UK and Portugal. A floating wind project is complex and has many interdependencies and interfaces. During all stages of the project several participants are expected to use a numerical model of the whole system and not only the part the participant has to design. Examples of this are the mooring and floater designer requiring a coupled model of the whole system including also the wind turbine, the operations team requiring a model of the system to plan towing and operations. All these stakeholders require a coupled model where the hydrodynamics, aerodynamics and structural physics of the system are captured with different levels of accuracy. In this paper, we will concentrate on a simplified model for the aerodynamic loading of the turbine in idling and standstill conditions that can be easily implemented in a simulation tool used for floater, mooring and marine operations studies. The method consists of using a subset of simulations at constant wind speed (ideally close to the wind speed required for the simulations) run on a detailed turbine model on a rigid tower and fixed foundation — normally run by the turbine designer. A proxy to the aerodynamic loads on the rotor and nacelle (RNA) is to take the horizontal yaw bearing loads. The process is then repeated for a range of nacelle yaw misalignments (for example every 15° for 360°). A look-up table with the horizontal yaw bearing load for the range of wind-rotor misalignments investigated is created. The simplified model of the aerodynamic loads on the RNA consists of a fixed blade (or wing) segment located at the hub, where aerodynamic drag and lift coefficients can be specified. Using the look-up tables created using the detailed turbine model, drag and lift coefficients are estimated as a function of the angle between the rotor and the wind direction. This representation of the aerodynamic loading on the RNA was then verified against full-field turbulent wind simulations in fixed and floating conditions using a multi-megawatt commercial turbine. The results for the parameters concerning the floater, mooring and marine operations design were monitored (e.g. tower bottom loads, offsets, pitch, mooring tensions) for extreme conditions and the errors introduced by this simplified rotor are generally lower than 4%. This illustrates that this simplified representation of the turbine can be used by the various parties of the project during the early stages of the design, particularly when knowing the loading within the RNA and on higher sections of the tower is not important.

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