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Viewing 1 to 30 of 2113
2016-09-27
Technical Paper
2016-01-8022
Petter Ekman, Roland Gardhagen, Torbjörn Virdung PhD, Matts Karlsson
Reducing energy consumption and emissions are ongoing challenges for the transport sector. The increased number of goods transports emphasize these challenges even more, as greenhouse gas emissions from these vehicles has increased by 20 % since 1990 in Sweden. One special case of goods transports is that of timber. Today in Sweden, around 2000 timber trucks transport around six billion ton kilometers every year. For every ton kilometer these vehicles use around 0.25 liter diesel, and there should exist large possibilities to reduce the fuel consumption and the emissions. These timber trucks spend most of their operation time travelling in speeds of around 80 km/h. At this speed aerodynamic drag contributes to around 30% of the total vehicle resistance, which makes the aerodynamic drag a significant part of the energy consumption. One of the big challenges with timber trucks is that they travel empty half of the time.
2016-09-27
Technical Paper
2016-01-8070
Prasad vegendla, Tanju Sofu, Rohit Saha, Mahesh Madurai Kumar, Long-Kung Hwang, Steven Dowding
Fan and Fan-shroud design is critical for underhood air flow management. The objective of this work is to demonstrate a method to optimize fan-shroud shape in order to maximize cooling air mass flow rates through the heat exchangers using the Adjoint Solver in STAR-CCM+®. Such techniques using Computational Fluid Dynamics (CFD) analysis enables the automotive/transport industry to reduce the number of costly experiments that they perform. This work presents the use of CFD as a simulation tool to investigate and assess the various factors that can affect the vehicle thermal performance. In heavy-duty trucks, the cooling package includes heat exchangers, fan-shroud, and fan. In this work, the STAR-CCM+® solver was selected and a java macro built to run the primal flow and the adjoint solutions sequentially in an automated fashion.
2016-09-27
Technical Paper
2016-01-8147
Justin J. Novacek, Bhargav Sowmianarayanan
Trailer positioning plays a significant role in the overall aerodynamics of a tractor-trailer combination and varies widely depending on configuration and intended use. In order to minimize aerodynamic drag over a range of trailer positions, adjustable aerodynamic devices like a trim tab may be utilized. For maximum benefit, it is necessary to determine the optimal position of the aerodynamic device for each trailer position. This may be achieved by characterizing a two-dimensional design space consisting of trailer height and tractor-trailer gap length, with aerodynamic drag as the response. CFD simulations carried out using a Lattice-Boltzmann based method were coupled with modeFRONTIER for the creation of multiple Kriging Response Surfaces. These response surfaces were employed to generate an optimal positioning map for the given aerodynamic device. This methodology was further refined by obtaining performance maps for multiple tractor configurations.
2016-09-27
Technical Paper
2016-01-8073
Long-Kung Hwang, Rohit Saha, Mahesh Madurai Kumar, Xingshi Wang, Fengchao Zhang, Xiaodan Zhang, Liu Yagui, Weiqing Sun, Yan Wang, Wei Cheng, Mingjin Lin
Higher heat rejection from engine due to higher emissions level and tighter under-hood packaging space often poses integration challenges for both engine and truck manufacturer. Cummins has to perform physical test for validation of the truck's cooling system capability in Chassis dyno at the end of truck's design stage. Cummins' cooling requirements are not met, usually it becomes a big bottleneck in terms of time and resource to redesign and re-select the cooling system components. So, the selection & verification of cooling module for the truck in early stages of design is critical for integration of engine, cooling module and truck. Use of different tools like 1D (like Kuli & LMS Amesim) and 3D simulation (ANSYS Fluent) tools, in the design phase trucks is demonstrated to analyze and validate the design of medium duty truck cooling system.
2016-09-27
Technical Paper
2016-01-8139
Santosh Nalanagula, Varadharajan G T
Aerodynamic Drag Reduction for Commercial Trucks Aerodynamic drag contributes to 50-60% of fuel consumption in trucks on highways. The limits of conventional wind tunnel testing have forced researchers to study about the drag and ways of reducing it computationally. Due to the stricter norms and eco-friendly approaches, truck manufacturers have begun to invest more for developing truck aerodynamics. This paper evaluates a European vehicle on European conditions. Drag reduction are mostly made by geometric changes. Pressure drag, a major drag for trucks as they run at lower speeds is produced by the shape of the object. Making streamlined bodies as trucks are tougher since it can affect its purpose. Therefore, addition of some components can suffice the needs. The changes in geometry have been implied and analysis for these geometrical changes are done to analyze the better geometry which can provide drag reduction features.
2016-09-27
Technical Paper
2016-01-8140
Devaraj Dasarathan, Ashraf Farag, Matthew Ellis
Recent regulations on greenhouse gas (GHG) emission standards for heavy-duty vehicles have prompted government agencies to standardize procedures assessing the aerodynamic performance of Class 8 tractor-trailers. The coastdown test procedure is the primary reference method to assess vehicle drag currently, while other valid alternatives include constant speed testing, computational fluid dynamics (CFD) simulations, and wind tunnel testing. In this paper, we correlate CFD simulation with 1/8th scale wind tunnel testing and highlight the impacts of wind tunnel testing on absolute performance compared to open road, full scale analysis including real world effects such as unsteady wind conditions. All scale model testing and CFD simulations were performed on a Class 8 tractor with a standard 53-foot dry-box trailer. The wind tunnel testing was performed in the Auto Research Center (ARC) wind tunnel.
2016-09-20
Technical Paper
2016-01-1999
Debabrata Pal, Frank Feng
Cooling of high current bus bars in aircraft power panels is performed by natural convection and radiation. Thermal analysis is done using Joule heating method where the heat dissipation in bus bar is computed based on current, specified resistivity, temperature coefficient of bus bar material and geometry of bus bar. In 3 phase AC application, there is additional heat dissipation due to skin effects and proximity effects. In addition, when the 3 phase AC is used to drive a motor at high frequency (1000-1400 Hz), this results in additional higher frequency harmonics, resulting in higher losses. In this paper a thermal and electrical FEA analysis is done for a bus bar system. For electrical loss model, Infolytica MAGNET is used to characterize losses in three parallel bus bars carrying AC at various frequencies. This loss analysis provided additional losses due to skin, proximity and higher frequency harmonics. Then this loss is incorporated the ICEPAK CFD thermal model.
2016-09-20
Technical Paper
2016-01-1994
Wei Wu, Yeong-Ren Lin, Louis Chow, Edmund Gyasi, John P. Kizito, Quinn Leland
For aircraft electromechanical actuator (EMA) cooling application, the main objectives in axial fan design are high pressure head and high efficiency over a wide operating range including speed variation 1x~3x and pressure 0.2~1atm variation. The fan is based on a thickness of 2.54 cm, 48 mm hub, 86 mm fan diameter. The purpose of this study is to characterize a fan's performance at various rotational speeds and various ambient pressures, from 0.2 atm to 1 atm. Methodology An 86-mm diameter axial fan for electromechanical actuators was designed. The blade shape was obtained by optimization design of the radial blade using CFD technique. Geometrical parameters describing the variations of the blade profile were determined by hub contour and fan’s required parameters given above. The 3,5, 7-blade configurations were compared with the optimal blade profile. A commercial brushless DC axial fan motor is chosen. The fan blades were 3-D printed and tested in a closed test loop.
2016-09-18
Technical Paper
2016-01-1929
Nimrod Kapas, Ajith Jayasundera
There is an increasing interest in transient thermal simulations of automotive brake systems using CFD software. This paper presents a detailed high-fidelity simulation tool for modeling complete braking cycles including both the deceleration and the acceleration phases. During braking, this model applies the total heat input directly at the friction interface on the contacting rotor and pad surfaces. Based on the conductive heat fluxes within the surrounding parts, the solver automatically determines the division of the thermal energy flowing from the friction interface into the solid volumes of the rotor and the pad. The convective heat transfer between the surfaces of solid parts and the cooling airflow is simulated through conjugate heat transfer, and radiative heat exchange between solid surfaces is captured by using the discrete ordinates model.
2016-06-15
Technical Paper
2016-01-1805
Florian Zenger, Clemens Junger, Manfred Kaltenbacher, Stefan Becker
Abstract A low pressure axial fan for benchmarking numerical methods in the field of aerodynamics and aeroacoustics is presented. The generic fan for this benchmark is a typical fan to be used in commercial applications. The design procedure was according to the blade element theory for low solidity fans. A wide range of experimental data is available, including aerodynamic performance of the fan (fan characteristic curve), fluid mechanical quantities on the pressure and suction side from laser Doppler anemometer (LDA) measurements, wall pressure fluctuations in the gap region and sound characteristics on the suction side from sound power and microphone array measurements. The experimental setups are described in detail, as to ease reproducibility of measurement positions. This offers the opportunity of validating aerodynamic and aeroacoustic quantities, obtained from different numerical tools and procedures.
2016-06-15
Technical Paper
2016-01-1830
Denis Blanchet, Luca Alimonti, Anton Golota
Abstract This paper presents new advances in predicting wind noise contribution to interior SPL in the framework of the Wind Noise German Working Group composed of Audi, Daimler, Porsche and VW. In particular, a new approach was developed that allows to fully describe the wind noise source using CFD generated surface pressure distribution and its cross-correlation function and apply this source on an SEA side glass. This new method removes the need to use a diffuse acoustic field or several plane waves with various incidence angle to approximate the correct acoustics source character to apply on the SEA side glass. This new approach results are compared with results previously published which use more deterministic methods to represent the side glass and the interior of a vehicle.
2016-06-15
Journal Article
2016-01-1808
Manfred Kaltenbacher, Andreas Hüppe, Aaron Reppenhagen, Matthias Tautz, Stefan Becker, Wolfram Kuehnel
Abstract We present a recently developed computational scheme for the numerical simulation of flow induced sound for rotating systems. Thereby, the flow is computed by scale resolving simulations using an arbitrary mesh interface scheme for connecting rotating and stationary domains. The acoustic field is modeled by a perturbation ansatz resulting in a convective wave equation based on the acoustic scalar potential and the substational time derivative of the incompressible flow pressure as a source term. We use the Finite-Element (FE) method for solving the convective wave equation and apply a Nitsche type mortaring at the interface between rotating and stationary domains. The whole scheme is applied to the numerical computation of a side channel blower.
2016-06-15
Journal Article
2016-01-1815
Augusto Della Torre, Gianluca Montenegro, Angelo Onorati
Abstract In the last decades numerical simulations have become reliable tools for the design and the optimization of silencers for internal combustion engines. Different approaches, ranging from simple 1D models to detailed 3D models, are nowadays commonly applied in the engine development process, with the aim to predict the acoustic behavior of intake and exhaust systems. However, the acoustic analysis is usually performed under the hypothesis of infinite stiffness of the silencer walls. This assumption, which can be regarded as reasonable for most of the applications, can lose validity if low wall thickness are considered. This consideration is even more significant if the recent trends in the automotive industry are taken into account: in fact, the increasing attention to the weight of the vehicle has lead to a general reduction of the thickness of the metal sheets, due also to the adoption of high-strength steels, making the vibration of the components a non negligible issue.
2016-05-01
Journal Article
2015-01-9148
Saeed Asgari, Shailendra Kaushik
Abstract A linear parameter varying (LPV) reduced order model (ROM) is used to approximate the volume-averaged temperature of battery cells in one of the modules of the battery pack with varying mass flow rate of cooling fluid using uniform heat source as inputs. The ROM runs orders of magnitude faster than the original CFD model. To reduce the time it takes to generate training data, used in building LPV ROM, a divide-and-conquer approach is introduced. This is done by dividing the battery module into a series of mid-cell and end-cell units. A mid-cell unit is composed of a cooling channel sandwiched in between two half -cells. A half-cell has half as much heat capacity as a full-cell. An end-cell unit is composed of a cooling channel sandwiched in between full-cell and a half-cell. A mass flow rate distribution look-up-table is generated from a set of steady-state simulations obtained by running the full CFD model at different inlet manifold mass flow rate samples.
2016-04-05
Technical Paper
2016-01-1054
Jorge Martins, Carlos Pereira, F.P. Brito
Abstract One way to increase efficiency and performance of 2-stroke engines is the addition of an exhaust valve to control the opening/closure of the exhaust port. With this implementation it is possible to change the exhaust timing for different conditions. However, conventional systems cannot change the exhaust opening and closure timings independently. The work herein presented shows the development of a new exhaust rotary valve enabling the control of the opening independently from the control of the closure of the exhaust port. The study is based on kinetic and thermodynamic analysis. Some manufacturers use exhaust rotary valves but none of them performs a fully rotary motion. This kind of motion has various benefits such as smoothness and most notably the ability to control both the opening and the closure timing of the exhaust independently. Regarding the kinematic analysis, a simple model was created to determine the most suitable valve angles.
2016-04-05
Technical Paper
2016-01-1022
Ahsanul Karim, Anthony Morelli, Keith Miazgowicz, Brian Lizotte, Robert Wade
The use of Swirl-Vanes or Inlet Guide Vanes (IGV) in gas engines is well-known and has demonstrated their ability to improve compressor surge margin at low flow rates. But, the use of swirl-vanes is not too common in large diesel engine turbo-chargers where compressor housing inlet has some form of Casing-Treatment (CT). Recently, Ford engineers tested swirl-vanes in a diesel engine turbocharger where the compressor inlet had a ported shroud casing-treatment and the experimental data showed no improvement in surge margin. Computational Fluid Dynamics (CFD) analyses were performed to investigate reasons why the surge margin did not improve after introducing swirl-vanes at the compressor inlet. The CFD results showed strong interactions between swirling flow at the compressor inlet and flow stream coming out of the compressor inlet casing-treatment.
2016-04-05
Technical Paper
2016-01-1018
Shan Wang, ZhenFeng Zhao, Shuanlu Zhang, Jinxiang Liu, Yuhang Liu
Abstract In this paper, a new method for the driving of the hydraulic free piston engine (HFPE) is proposed. Hydraulic differential drive achieves the compression stroke automatically rather than special recovery system, which has a great influence on the engine dynamic performance. The purpose of this paper is to solve the key operation and control problems for HFPE to commix fuel with air. HFPE adopts two-stroke loop-scavenging and semi-direct injection. The semi-direct injection nozzle is located in the liner wall inside the main intake port, with the axes oriented towards the piston at the Bottom Dead Center (BDC). Different scavenging pressures and injection angles result in different impacts on the mixture of fuel and air in the cylinder. This study analyzes the changes of the combustion heat release rate by simulation.
2016-04-05
Technical Paper
2016-01-1346
Tomoyuki Hosaka, Taisuke Sugii, Eiji Ishii, Kazuhiro Oryoji, Yoshihiro Sukegawa
Abstract We developed the numerical simulation tool by using OpenFOAM® and in-house simulation codes for Gasoline Direct Injection (GDI) engine in order to carry out the precise investigation of the throughout process from the internal nozzle flow to the fuel/air mixture in engines. For the piston/valve motions, a mapping approach is employed and implemented in this study. In the meantime, the spray atomization including the liquid-columnbreakup region and the secondary-breakup region are simulated by combining the different numerical approaches applied to each region. By connecting the result of liquid-column-breakup simulation to the secondary-breakup simulation, the regions which have different physical phenomena with different length scales are seamlessly jointed; i.e., the velocity and position of droplets predicted by the liquid-column-breakup simulation is used in the secondary breakup simulation so that the initial velocity and position of droplets are transferred.
2016-04-05
Technical Paper
2016-01-1356
Can Li, Yadong Deng, Yuhua Xin
Abstract As a key component of airstream system equipped in the road sweeper, the structure of the suction nozzle determines its internal flow field distribution, which affects the dust-sucking efficiency to a great degree. This research is aiming to determine a better suction nozzle structure. Starting with an analysis of the one used in a certain type of road sweeper, the initial model of the suction nozzle is established, and the internal flow field is simulated with typical computational fluid dynamics (CFD) software named FLUENT. Based on the simulation results, the dust-sucking capability of the initial structure is evaluated from the aspects of pressure and velocity distribution. Furthermore, in order to explore the influence of different structural parameters on the flow field distribution within the suction nozzle, models with different cavity heights and shoulder angles are established, and Univariate Method is utilized to analyze the contrast models.
2016-04-05
Technical Paper
2016-01-1608
Asiful Islam, Ben Thornber
Abstract Current vehicle aerodynamic development makes extensive use of Computational Fluid Dynamics (CFD) to enable cost-effective design and parametric exploration. Although larger-scale, high fidelity simulations are increasingly popular, practical Reynolds number ranges (105-108) necessitate hybrid modelling approaches which offer alternatives to fully-resolved Large-Eddy Simulation (LES) for predictive capability of separated, turbulent flows. A detailed aerodynamic investigation is conducted over a SAE Notchback model which experiences subtle pressure-induced separation near the roof-backlight junction and shear layer roll-up and a low-pressure wake at the rear. Computational results were generated by a novel Detached-Eddy Simulation (DES) algorithm implemented in a high-order, compressible CFD code FLAMENCO.
2016-04-05
Technical Paper
2016-01-1618
Yoshihiro Okada, Takuji Nakashima, Makoto Tsubokura, Yousuke Morikawa, Ryousuke Kouno, Satoshi Okamoto, Tanaka Matsuhiro, Takahide Nouzawa
Abstract A road vehicle’s cornering motion is known to be a compound motion composed mainly of forward, sideslip and yaw motions. But little is known about the aerodynamics of cornering because little study has been conducted in this field. By clarifying and understanding a vehicle’s aerodynamic characteristics during cornering, a vehicle’s maneuvering stability during high-speed driving can be aerodynamically improved. Therefore, in this study, the aerodynamic characteristics of a vehicle’s cornering motion, i.e. the compound motion of forward, sideslip and yaw motions, were investigated. We also considered proposing an aerodynamics evaluation method for vehicles in dynamic maneuvering. Firstly, we decomposed cornering motion into yaw and sideslip motions. Then, we assumed that the aerodynamic side force and yaw moment of a cornering motion could be expressed by superposing linear expressions of yaw motion parameters and those of sideslip motion parameters, respectively.
2016-04-05
Technical Paper
2016-01-1617
Yoshinobu Yamade, Chisachi Kato, Shinobu Yoshimura, Akiyoshi Iida, Keiichiro Iida, Kunizo Onda, Yoshimitsu Hashizume, Yang Gou
Abstract A wall-resolving Large Eddy Simulation (LES) has been performed by using up to 40 billion grids with a minimum grid resolution of 0.1 mm for predicting the exterior hydrodynamic pressure fluctuations in the turbulent boundary layers of a test car with simplified geometry. At several sampling points on the car surface, which included a point on the side window, the door panel, and the front fender panel, the computed hydrodynamic pressure fluctuations were compared with those measured by microphones installed on the surface of the car in a wind tunnel, and effects of the grid resolution on the accuracy of the predicted frequency spectra were discussed. The power spectra of the pressure fluctuations computed with 5 billion grid LES agreed reasonably well with those measured in the wind tunnel up to around 2 kHz although they had some discrepancy with the measured ones in the low and middle frequencies.
2016-04-05
Technical Paper
2016-01-1616
Keiichiro Iida, Kunizo Onda, Akiyoshi Iida, Chisachi Kato, Shinobu Yoshimura, Yoshinobu Yamade, Yoshimitsu Hashizume, Yang Guo
Abstract One-way coupled simulation method that combines CFD, structural and acoustical analyses has been developed aiming at predicting the aeroacoustical interior noise for a wide range of frequency between 100 Hz and 4 kHz. Statistical Energy Analysis (SEA) has been widely used for evaluating transmission of sound through a car body and resulting interior sound field. Instead of SEA, we directly computed vibration and sound in order to investigate and understand propagation paths of vibration in a car body and sound fields. As the first step of this approach, we predicted the pressure fluctuations on the external surfaces of a car by computing the unsteady flow around the car. Secondly, the predicted pressure fluctuations were fed to the subsequent structural vibration analysis to predict vibration accelerations on the internal surfaces of the car.
2016-04-05
Technical Paper
2016-01-1683
Blago B. Minovski, Lennart Lofdahl, Peter Gullberg
Abstract Presented are results from numerical investigations of buoyancy driven flow in a simplified representation of an engine bay. A main motivation for this study is the necessity for a valid correlation of results from numerical methods and procedures with physical measurements in order to evaluate the accuracy and feasibility of the available numerical tools for prediction of natural convection. This analysis is based on previously performed PIV and temperature measurements in a controlled physical setup, which reproduced thermal soak conditions in the engine compartment as they occur for a vehicle parked in a quiescent ambient after sustaining high thermal loads. Thermal soak is an important phenomenon in the engine bay primarily driven by natural convection and radiation after there had been a high power demand on the engine. With the cooling fan turned off and in quiescent environment, buoyancy driven convection and radiation are the dominating modes of heat transfer.
2016-04-05
Technical Paper
2016-01-1600
Pruthviraj Mohanrao Palaskar, Vivek Kumar, Rohit Vaidya
Abstract Important vehicle performance parameters such as, fuel economy and high speed stability are directly influenced by its aerodynamic drag and lift. Wind tunnel testing to asses these parameters requires heavy investment especially when test wind tunnel is not available in the country where vehicle development center is present. Hence to save cost and to compress development time, it is essential to asses and optimize parameters of a vehicle in very early stages of development. Using numerical flow simulations optimization runs can be carried out digitally. Industry demands prediction of aerodynamic drag and lift coefficients (CD,CL) within an accuracy of a few counts, consuming minimal HPC resources and in a short turnaround time. Different OEMs deploy different testing methods and different softwares for numerical simulations.
2016-04-05
Technical Paper
2016-01-1604
Anton Kabanovs, Max Varney, Andrew Garmory, Martin Passmore, Adrian Gaylard
Abstract This paper focuses on methods used to model vehicle surface contamination arising as a result of rear wake aerodynamics. Besides being unsightly, contamination, such as self-soiling from rear tyre spray, can degrade the performance of lighting, rear view cameras and obstruct visibility through windows. In order to accurately predict likely contamination patterns, it is necessary to consider the aerodynamics and multiphase spray processes together. This paper presents an experimental and numerical (CFD) investigation of the phenomenon. The experimental study investigates contamination with controlled conditions in a wind tunnel using a generic bluff body (the Windsor model.) Contamination is represented by a water spray located beneath the rear of the vehicle.
2016-04-05
Technical Paper
2016-01-1606
Charalampos Kounenis, Sabine Bonitz, Emil Ljungskog, David Sims-Williams, Lennart Lofdahl, Alexander Broniewicz, Lars Larsson, Simone Sebben
Abstract The aerodynamic drag, fuel consumption and hence CO2 emissions, of a road vehicle depend strongly on its flow structures and the pressure drag generated. The rear end flow which is an area of complex three-dimensional flow structures, contributes to the wake development and the overall aerodynamic performance of the vehicle. This paper seeks to provide improved insight into this flow region to better inform future drag reduction strategies. Using experimental and numerical techniques, two vehicle shapes have been studied; a 30% scale model of a Volvo S60 representing a 2003MY vehicle and a full scale 2010MY S60. First the surface topology of the rear end (rear window and trunk deck) of both configurations is analysed, using paint to visualise the skin friction pattern. By means of critical points, the pattern is characterized and changes are identified studying the location and type of the occurring singularities.
2016-04-05
Technical Paper
2016-01-1582
Dirk Wieser, Sabine Bonitz, Lennart Lofdahl, Alexander Broniewicz, Christian Nayeri, Christian Paschereit, Lars Larsson
Abstract Flow visualization techniques are widely used in aerodynamics to investigate the surface trace pattern. In this experimental investigation, the surface flow pattern over the rear end of a full-scale passenger car is studied using tufts. The movement of the tufts is recorded with a DSLR still camera, which continuously takes pictures. A novel and efficient tuft image processing algorithm has been developed to extract the tuft orientations in each image. This allows the extraction of the mean tuft angle and other such statistics. From the extracted tuft angles, streamline plots are created to identify points of interest, such as saddle points as well as separation and reattachment lines. Furthermore, the information about the tuft orientation in each time step allows studying steady and unsteady flow phenomena. Hence, the tuft image processing algorithm provides more detailed information about the surface flow than the traditional tuft method.
2016-04-05
Technical Paper
2016-01-1584
Kenichi Ando, Naoshi Kuratani, Hideo Fukuda
Abstract An aerodynamic styling evaluation system employed at an early automotive development stage was constructed. The system based on CFD consists of exterior model morphing, computational mesh generation, flow calculation and result analysis, and the process is automatically and successively executed by process automation software. Response surfaces and a parallel coordinates chart output by the system allow users to find a well-balanced exterior form, in terms of aerodynamics and exterior styling, in a wide design space which are often arduous to be obtained by a conventional CAE manner and scale model wind tunnel testing. The system was designed so that 5-parameter study is completed within approximately two days, and consequently, has been widely applied to actual exterior styling development. An application for a hatchback vehicle is also introduced as an actual example.
2016-04-05
Technical Paper
2016-01-1586
Sinisa Krajnovic, Guglielmo Minelli, Branislav Basara
Partially-Averaged Navier-Stokes Simulations (PANS) were made of flow around a generic vehicle influenced by side wind at four different yaw angles to investigate the prediction capabilities of PANS. Comparisons with results of LES show clear advantages of PANS in predicting pressure-induced separation resulting in the trailing vortices aligned with the direction of the flow. Poorer agreement was obtained in the near wake when the boundary layer separates at the end of the surface at the rear end. A possible explanation for the lack of accuracy at the rear end of the body was found in the formulation of the switching coefficient fk which produces too low values resulting in too low eddy viscosity in this region.
Viewing 1 to 30 of 2113

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