Approaches for Acoustics Simulation for Automotive … for Acoustics Simulation for Automotive Air...
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Approaches for Acoustics Simulation for Automotive Air Induction & Exhaust Systems Fabiano Bet Gerald Seider Simon Bless Vienna, 18 March, 2014
Transcript of Approaches for Acoustics Simulation for Automotive … for Acoustics Simulation for Automotive Air...
Approaches for Acoustics Simulation
for Automotive Air Induction & Exhaust
Systems
Fabiano Bet
Gerald Seider
Simon Bless
Vienna, 18 March, 2014
Consulting, Engineering Services & Virtual Test Center
Simulation and Analysis of
complex fluid flow and heat
transfer systems for
engineering and industrial
applications
Virtual Performance Testing
for automotive accessory units
InDesA GmbH Carl-Zeiss-Ring 19a D-85737 Ismaning Phone +49 (89) 552 7978-10 Fax +49 (89) 552 7978-29 www.InDesA.de
Company Profile
1D System Analysis
GT-SUITE
3D CFD/CHT Analysis
STAR Global Conference Vienna, 18.03.2014 page 3
Acoustics Simulation for Automotive Systems Introduction
From engine Driving noise Body vibrations Mechanic and wheel noise
Aeroacoustics: “…branch of acoustics that studies noise generation via fluid motion or aerodynamic
forces interaction…” (source: Wikipedia)
STAR Global Conference Vienna, 18.03.2014 page 4
Acoustics Simulation for Automotive Systems Introduction
Noise generation via fluid motion: e.g. Blowing in a bottle
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Acoustics Simulation for Automotive Systems Introduction
Noise Transmission: e.g. Speaking into a loudhailer
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Acoustics Simulation for Automotive Systems Overview
1. Design of a high frequency broad band resonator for an engine air induction system
2. Simulation of exhaust sound pressure level for different tail pipe designs.
STAR Global Conference Vienna, 18.03.2014 page 7
Acoustics Simulation for Automotive Systems
air box w/o filter
air intake (open, echoic)
to compressor
HHR
*) random signal with constant power spectral density (intensity)
Simplified Air Intake System
white noise*) speaker
Acoustic resonators and dampers
air box
Helmholtz resonator (HHR)
broad band resonance chambers
resonance chambers
Virtual Transmission Loss Test Bench
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Acoustics Simulation for Automotive Systems Signal Processing and Analysis
signal analyzer
GT-SUITE attenuated frequencies
FFT noise reduction insertion loss transmission loss
pressure sensors
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Acoustics Simulation for Automotive Systems Transmission Loss Analysis for Air Box
<700Hz, broad band attenuation due to expansion in air box
> 1000 Hz narrow band attenuation due to reflections in airbox
air box
alternative air box
connection
higher order response
STAR Global Conference Vienna, 18.03.2014 page 10
Acoustics Simulation for Automotive Systems Transmission Loss for Air Box & HRR
HRR
Helmholtz Resonator is used to attenuate specific frequencies (here: 80Hz)
to build broad band high frequency resonator reflections of airbox are used.
Resonator chambers must be added to fill the gaps.
… fill the gaps for broad band attenuation
HRR
Helmholtz Resonator (HRR)
air box design II
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Acoustics Simulation for Automotive Systems Transmission Loss for 1st Chamber
chamber response frequency: 1320 Hz
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Acoustics Simulation for Automotive Systems Transmission Loss for 2nd Chamber
chamber response frequency: ~2050 Hz
higher order response
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Acoustics Simulation for Automotive Systems Transmission Loss for 3rd Chamber
chamber response frequency: ~2600 Hz
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Acoustics Simulation for Automotive Systems Transmission Loss of Broad Band Resonator
3 chamber broad band resonator in
combination with airbox reflections
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Acoustics Simulation for Automotive Systems
-2.78E-16
0.02
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0.1
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0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00
Am
plit
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x/x_ref
1320 Hz
2050 Hz
2600 Hz
Wave Analysis for 90° Bent
inner pressure sensors
0
0.02
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0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00
Am
plit
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1320 Hz
2050 Hz
2600 Hzouter pressure sensors
x
FFT outer pressure sensors
FFT inner pressure sensors
higher amplitudes occur at outer radius, thus more
effective for chamber connection.
high frequency resonators can be shifted to position
where amplitudes are highest.
inner radius is less effective for chamber connection
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Acoustics Simulation for Automotive Systems Splitter Baffle in 90° Bent as Resonator
splitter wall
phase shift through different path lengths and wave cancellation when maxima meet minima at the end of splitter baffle
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Acoustics Simulation for Automotive Systems Overview
1. Design of a high frequency broad band resonator for an engine air induction system
2. Simulation of exhaust sound pressure level for different tail pipe designs.
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Acoustics Simulation for Automotive Systems Different tail pipe design
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Acoustics Simulation for Automotive Systems Different tail pipe design
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Acoustics Simulation for Automotive Systems Different tail pipe design
0,5 m
0,3 m
Microphone
Case #1
Case #2
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Acoustics Simulation for Automotive Systems Different tail pipe design
STAR Global Conference Vienna, 18.03.2014 page 22
Acoustics Simulation for Automotive Systems Outlook
Driving trough Simulation (coming soon)
…thanks for Your attention!
