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Viewing 1 to 30 of 2530
2015-06-25
Event
This session is to present numerical and experimental work pertaining to noise due to flow around the vehicle body, such as flow-induced interior noise, flow over protrusions, sunroofs, windows, noise from ventilation systems, or flow noise in exhaust system. Papers on aerodynamics alone without sound are excluded. Numerical studies may include new models or models based on existing theory as long as they are adequately supported by experimental or theoretical verifications.
2015-06-24
Event
This session is to present numerical and experimental work pertaining to noise due to flow around the vehicle body, such as flow-induced interior noise, flow over protrusions, sunroofs, windows, noise from ventilation systems, or flow noise in exhaust system. Papers on aerodynamics alone without sound are excluded. Numerical studies may include new models or models based on existing theory as long as they are adequately supported by experimental or theoretical verifications.
2015-06-24
Event
This session is to present numerical and experimental work pertaining to noise due to flow around the vehicle body, such as flow-induced interior noise, flow over protrusions, sunroofs, windows, noise from ventilation systems, or flow noise in exhaust system. Papers on aerodynamics alone without sound are excluded. Numerical studies may include new models or models based on existing theory as long as they are adequately supported by experimental or theoretical verifications.
2015-06-15
Technical Paper
2015-01-2321
Nicholas Oettle, Andrew Bissell, Sivapalan Senthooran, Mohammed Meskine
Car manufacturers put large efforts into reducing wind noise to improve the comfort level of their cars. Each component of the vehicle is designed to meet its individual noise target to ensure the wind noise passenger comfort level inside the vehicle is met. Sunroof designs are tested to meet low-frequency buffeting targets as well as broadband noise targets for the sunroof in vent position and any noise generated by deflectors. Experimentally testing designs and making changes to meet these design targets typically involves high cost prototypes, expensive wind tunnel sessions, and potentially late design changes. To reduce the associated costs as well as development times, there is strong motivation for the use of a reliable numerical prediction capability early in the vehicle design process.
2015-06-15
Technical Paper
2015-01-2326
Denis Blanchet, Anton Golota
Recent developments in the prediction of the contribution of wind noise to the interior SPL have opened a realm of new possibilities. The main physical mechanisms related to noise generation within a turbulent flow and transmission through the vehicle greenhouse are nowadays better understood. Several simulation methods such as CFD, FEM, BEM, FE/SEA Coupled and SEA can be coupled together to represent the physical phenomena involved. The main objective being to properly represent the convective and acoustic component within the turbulent flow to ensure proper computation of the wind noise contribution to the interior SPL of a vehicle. This paper presents comparisons between simulations results and measurements for various configurations such as i) with and without mirror, ii) various A-Pillar shapes, iii) various vehicle speeds and finally iv) various yaw angles.
2015-06-15
Technical Paper
2015-01-2331
Alexander Schell, Vincent Cotoni
Aero-vibro-acoustic prediction of interior noise associated with exterior flow requires accurate predictions of both fluctuating surface pressures across the exterior of a vehicle and efficient models of the vibro-acoustic transmission of these surfaces pressures to the interior of a vehicle. The frequency range of interest varies depending on the region and source of interest. For noise transmitted through a sideglass the frequency range of interest is typically from 1-5kHz. The vibro-acoustic methods used to describe noise and vibration transmission also depend on the frequency range of interest. At higher frequencies methods like statistical energy analysis (SEA) are particularly well suited for describing the response of a trimmed cabin due to the short wavelength response of the interior acoustic space and sound package. An accurate prediction of fluctuating surface pressures also requires an accurate model of the flow over the exterior of the vehicle.
2015-06-15
Technical Paper
2015-01-2329
Paolo Di Francescantonio, Charles Hirsch, Piergiorgio Ferrante, Katsutomo Isono
The prediction of the broadband noise generated by the flow interaction with solid bodies such as for example side mirror noise, exhaust pipe noise, or ventilation and air conditioning noise require in principle the execution of extremely high demanding unsteady CFD simulations that nowadays cannot be afforded in an industrial environment. Therefore research efforts have been focused on alternative approaches that could permit to obtain engineering accurate results with much reduced computational efforts by stochastically reconstructing the turbulent velocity field starting from a steady RANS analysis. Two main families of methods have been introduced up to now, SNGR [1], and RPM[2], but applications in industrial environment are still limited mainly due to the lack of reliability of these methods and the need to introduce some tuning parameters.
2015-06-15
Technical Paper
2015-01-2327
Wind noise is one of the important NVH attributes that impacts customer sensation of vehicle interior quietness. Among many factors that influence wind noise performance, the amount of dynamic door deflection under the pressure load due to fast movement of a vehicle plays an key roll. The excessive deflection could potentially cause opened sealing gap, a.k.a. aspiration leakage, which creates a path through which the exterior aerodynamically induced noise propagates into the vehicle cabin. The dynamic door deflection can be predicted using CFD and CAE tools. This work looks into the internal pressure issue associated with the dynamic load setup during the CAE analysis. The capability of predicting the internal pressure due to high wind speed outside of a vehicle still has not been developed, and the work is based on the wind tunnel measurement involving several vehicles.
2015-06-15
Technical Paper
2015-01-2127
Andrea Munzing, Franck Hervy, Stephane Catris
A helicopter blade profile was tested in the DGA Aero-engine’s S1 icing wind tunnel in Saclay, France in winter 2013/2014. The 2D airfoil was a helicopter main rotor blade profile. Ice accretion tests have been performed to assess the profile’s time dependant aerodynamic behaviour during ice accretion. Real ice shapes were collected after each icing test. Moreover, iced profile polars were realized over a large range of angle of attack until stall. This paper presents the test set up, the test model and the test results. The test results presented in this paper are dry air and iced profile polars as well as ice shapes. The complete iced profile polars and the aerodynamic behaviour in time of the iced blade profile during ice accretion will be used for adjusting and validating prediction tools like Airbus Helicopter’s analytical iced rotor performance degradation model and they will aid to appraise the rotor loads evolution in icing conditions.
2015-06-15
Technical Paper
2015-01-2323
Abdelhakim AISSAOUI, Ravindra S Tupake, Vilas Bijwe, Mohammed Meskine, Franck Perot, Alain BELANGER, Rohit J Vaidya
F or the automotive industry, acoustic comfort is of increasing importance and changes in the market make the HVAC system noise quality a question to be addressed as early as possible during the vehicle development process. On one hand, the so-called traditional sources of annoyance such as engine, road-tires contact, exhaust systems and wind-noise have been significantly reduced for most traditional combustion engine vehicles. On the other hand, the rapid expansion of hybrid and electric vehicles and idling stop systems increases the importance of sources such as HVAC systems considered in the past as secondary. At high mass flow rate, the flow-induced contribution from the ducts and registers is the main source of noise in the mid to high frequency ranges and is more important than the HVAC structure borne and blower engine contributions.
2015-06-15
Technical Paper
2015-01-2118
Sergey Alekseyenko, Michael Sinapius, Martin Schulz, Oleksandr Prykhodko
In spite of wide theoretical and experimental studies of icing problem that have been held up to recent times, nevertheless, the most dangerous flights regimes as in the presence of supercooled large droplets or in supercooled rain remain studied not enough. Also the range of parameters that corresponds to the exploitation modes of aircrafts with relatively small heights and speeds of flight like airplanes of small aviation, helicopters, UAV etc. because of the complexity of the icing processes are still not covered. The aim of this work is to answer the next question: which an actual process of interaction of supercooled large water droplets with growing ice surface at small speeds of flight and which physics of falling moisture freezing process on the icing surface is. Thus, the work presents the results of experiments conducted in order to obtain the photographic data on how the interaction between the supercooled water droplets and the icing aerodynamic surface occurs.
2015-06-15
Technical Paper
2015-01-2080
Roger J. Aubert
While the industry is making consistent progress in predicting aerodynamic performance impact from ice accretion on rotor blade and ability to reliably design thermal anti-icing and/or deicing protection systems, ice shedding, natural or induced, is trailing behind both in terms of understanding the physics of impact ice adhesion and cohesion, mechanical fracture and energy dissipation upon impact on airframe or rotor systems. It is only recently that attention dedicated to the understanding of impact ice shedding on rotors has increased. Reference 1 summarizes the mechanical properties of ice. However, more recent test results (Reference 2 and 3) showed different results. It was therefore concluded that a data base more representative of helicopter operation was necessary. It is the intent of this paper to summarize the differences in test results and provide additional considerations for analytical modeling of the ice shedding process on a rotor blade.
2015-06-15
Technical Paper
2015-01-2322
Bastien Ganty, Jonathan Jacqmot, Ze Zhou
At high cruising speed, the car A-pillars generate turbulent air flow. The resulting aerodynamic pressure applied on the windows significantly contributes to the total cabin noise. In order to predict this particular noise contribution, the physic of both the flow and the cabin needs to be accurately modeled. This paper presents an efficient methodology to predict the turbulent noise transmission through the car windows. The method relies on a two-step approach: the first step is the computation of the exterior turbulent field using an unsteady CFD solver (EXA PowerFlow); the second step consists in the computation of the acoustic propagation inside the cabin using a finite element vibro-acoustic solver (Actran). The simplified car cabin of Hyundai Motor Company, studied in this paper, involves aluminum skin, windows, sealant, inner air cavity and acoustic treatment (porous material, damping layer). A pure vibro-acoustic model with hammer shock excitation on a window is first built.
2015-06-15
Technical Paper
2015-01-2330
Christian Y. Glandier, Oskar Prill, Mark Eiselt
With the reduction of engine and road noise, wind has become an important source of interior noise when cruising at highway speed. The challenges of weight reduction, performance improvement and reduced development time call for stronger support of the development process by numerical methods. CFD and finite element (FE) vibroacoustic computations have reached a level of maturity that makes it possible and meaningful to chain these methods for wind noise prediction. This paper presents a method used for coupling time domain CFD computations with a finite element vibroacoustic model of a vehicle for the prediction of low frequency wind noise below 500 Hz. The procedure is based on time segmentation of the excitation load and transformation into the frequency domain for the vibroacoustic computations. It requires simple signal processing and preserves the random character as well as the spatial correlation of the excitation signal.
2015-06-15
Technical Paper
2015-01-2328
Barbara Neuhierl, Sivapalan Senthooran, Reinier Toppinga, Anke Jäger, Maarten Brink, Timo Lemke, Philippe Moron, Raghu Mutnuri
The object of the validation study presented in this paper is a generic vehicle, the so-called SAE body, developed by a consortium of german car manufacturers (Audi, Daimler, Porsche, Volkswagen). It consists of a simplified cabin whose interior can be equipped with either reverberant or partly absorbing walls. To obtain more realistic flow and pressure excitation typical for production vehicles, an a-pillar and a series rear view mirror were attached to the exterior surface. Furthermore the test object contains a glass side window, allowing noise transmission to the interior. Many experiments have been performed by the abovementioned consortium on this object in the past to investigate its behavior when exposed to fluid flow. Some of these experiments were used to validate the simulation results discussed in the present paper.
2015-06-15
Technical Paper
2015-01-2324
Hangsheng Hou, Guiping Yue
When a sunroof opens to let the fresh air in during driving, there might be several noise issues associated with it. The most common and important one is the wind throb issue, which is normally resolved by installing a wind deflector with sufficient height. However with the wind throb issue gone, other sound quality problems may surface. The most obvious one is the hissing noise, which occurs often in higher speed range. This work investigates a sunroof deflector deployment strategy considering wind throb, hissing noise and other psychoacoustic attributes that could be felt subjectively by a customer. The goal is to optimize sound quality associated with an open sunroof, potentially targeting the most NVH demanding customers in the premium vehicle segment.
2015-06-15
Technical Paper
2015-01-2325
Paul Bremner, Chris Todter, Scott Clifton
Title: Sideglass Turbulence and Wind Noise Sources Measured with a High Resolution Surface Pressure Array Authors: Paul Bremner – AeroHydroPLUS, Del Mar CA 92104 USA Chris Todter – Keppel Professional Services, San Diego CA 92107 Scott Clifton – c/o AeroHydroPLUS, Del Mar CA 92104 USA The authors report on the design and use of high resolution micro-electro-mechanical (MEMS) microphone arrays for automotive wind noise engineering. The arrays integrate both sensors and random access memory (RAM) chips on a flexible circuit board that eliminates high channel count wiring and allows the array to be deployed on automobile surfaces in a convenient “stick-on/peel-off” configuration. These arrays have application to the quantitative evaluation of interior wind noise from measurements on a clay model in the wind tunnel, when used in conjunction with a body vibro-acoustic model.
2015-06-15
Technical Paper
2015-01-2162
Krzysztof Szilder, Edward Lozowski
Atmospheric icing resulting from freezing rain, freezing drizzle and freezing cloud droplets occurs when airborne supercooled water drops freeze on objects they encounter. This process is especially hazardous to aircraft, when the build-up of ice changes the stability and control characteristics of the aerodynamic surfaces. Ice can also be shed with disastrous consequences, if it is ingested into engines, strikes the aircraft or leads to unbalanced aerodynamics forces. Ice accretion is a complex phenomenon involving 3-D multi-phase flow, heat transfer, and gravitational, viscous, surface tension and shear forces. An ability to predict how ice accretes on engineering structures is essential to the prediction of its associated aerodynamic penalties. We have developed an original icing modelling capability, called the “morphogenetic” approach, based on a discrete formulation and emulation of ice formation physics.
2015-04-23
Event
This 7 part session focuses on aerodynamic development, drag reduction and fuel economy, handling and stability, cooling flows, surface soiling and water management, vehicle internal environment, tire aerodynamics and modelling, aeroacoustics, structural response to aerodynamic loading, simulating the on-road environment, onset flow turbulence, unsteady aerodynamics, fundamental flow structures, new test methods and facilities, and new applications of computational fluid dynamics simulation
2015-04-23
Event
This 7 part session focuses on aerodynamic development, drag reduction and fuel economy, handling and stability, cooling flows, surface soiling and water management, vehicle internal environment, tire aerodynamics and modelling, aeroacoustics, structural response to aerodynamic loading, simulating the on-road environment, onset flow turbulence, unsteady aerodynamics, fundamental flow structures, new test methods and facilities, and new applications of computational fluid dynamics simulation
2015-04-22
Event
The purpose of this session is to bring awareness among the automotive aerodynamics, thermal and hydraulic systems development community to address the need of reliability analysis and robust design to improve the overall product quality. This session also introduces CAE based optimization of aero-thermal and fluid systems to improve automotive fuel economy. This session presents papers covering both testing and simulation.
2015-04-22
Event
This 7 part session focuses on aerodynamic development, drag reduction and fuel economy, handling and stability, cooling flows, surface soiling and water management, vehicle internal environment, tire aerodynamics and modelling, aeroacoustics, structural response to aerodynamic loading, simulating the on-road environment, onset flow turbulence, unsteady aerodynamics, fundamental flow structures, new test methods and facilities, and new applications of computational fluid dynamics simulation
2015-04-22
Event
This 7 part session focuses on aerodynamic development, drag reduction and fuel economy, handling and stability, cooling flows, surface soiling and water management, vehicle internal environment, tire aerodynamics and modelling, aeroacoustics, structural response to aerodynamic loading, simulating the on-road environment, onset flow turbulence, unsteady aerodynamics, fundamental flow structures, new test methods and facilities, and new applications of computational fluid dynamics simulation
2015-04-21
Event
This 7 part session focuses on aerodynamic development, drag reduction and fuel economy, handling and stability, cooling flows, surface soiling and water management, vehicle internal environment, tire aerodynamics and modelling, aeroacoustics, structural response to aerodynamic loading, simulating the on-road environment, onset flow turbulence, unsteady aerodynamics, fundamental flow structures, new test methods and facilities, and new applications of computational fluid dynamics simulation
Viewing 1 to 30 of 2530

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