Determination of noise sources within a high-speed jet via simultaneous acoustic measurements and real-time flow

2001 ◽  
Author(s):  
J. Hileman ◽  
B. Thurow ◽  
M. Samimy
Keyword(s):  
Real Time ◽  
High Speed ◽  
Acoustic Measurements ◽  
Noise Sources ◽  
Time Flow

scholarly journals Exploring Noise Sources Using Simultaneous Acoustic Measurements and Real-Time Flow Visualizations in Jets

AIAA Journal ◽  
2002 ◽  
Vol 40 (12) ◽  
pp. 2382-2392 ◽  
Author(s):  
James Hileman ◽  
Brian Thurow ◽  
Mo Samimy
Keyword(s):  
Real Time ◽  
Acoustic Measurements ◽  
Noise Sources ◽  
Time Flow ◽  
Flow Visualizations

Improving Sub-pixel Estimation of Laser Stripe Reflection Center by Autoconvolution on FPGA

2021 ◽  
pp. 2250063
Author(s):  
Bogdan R. Marković ◽  
Jelena D. Ćertić
Keyword(s):  
Real Time ◽  
High Speed ◽  
Dynamic Environment ◽  
External Noise ◽  
Central Position ◽  
Operational Environment ◽  
Performance Goal ◽  
Noise Sources ◽  
Pixel Intensity ◽  
Laser Stripe

Modern laser scanners perform high-speed real-time image processing algorithms while operating in harsh industrial environments. Their performance goal is to extract the central position of the laser line reflection with Gaussian distribution. Traditional algorithms for sub-pixel estimation, such as the Center of Gravity (CG) or Parabolic Fit (PF), show poor performances under low SNR or if the pixels are saturated. Data pre-processing usually has a key role in suppressing the effects of various noise sources and dynamic environment, especially when the images are overexposed and the top of Gaussian pulse is flattened. Both in simulation and in experiment, this study explains a method that improves the accuracy of estimation of the laser stripe reflection center, by using an autoconvolution for extending the bit-width of pixel intensity. Autoconvolution of the image line is an efficient real-time pre-processing filtering method for improving the accuracy of CG calculation. The proposed algorithm is implemented on Field-Programmable Gate Arrays (FPGAs) and experimentally validated at real operational environment. It is shown that this method can reduce the error of CG laser reflection center estimation for more than one pixel in size when the image is highly affected by external noise sources and ambient light.

Investigation of Acoustic Phenomena at the Inlet and the Outlet of a Centrifugal Compressor for Pressure Ratio 4.5

2001 ◽  
Author(s):  
H.-J. Feld ◽  
S. Aschenbrenner ◽  
R. Girsberger
Keyword(s):  
Centrifugal Compressor ◽  
High Speed ◽  
Pressure Ratio ◽  
Sound Field ◽  
Acoustic Measurements ◽  
Noise Sources ◽  
Measurement Plane ◽  
Compressor Inlet ◽  
Fundamental Insight ◽  
Insight Into

The effects of the interaction between impeller and diffuser and the influence of distortions in the inlet flow on noise generation in a high speed centrifugal compressor were investigated. Therefore, an existing test rig was modified to allow acoustic measurements in the upstream and downstream ducts of the compressor. Anechoic ends designed according to the standards for low speed fans were inserted at both sides of the compressor in order to prevent disturbing reflections. Three slit tube microphone probes were installed in each duct to determine the noise level at the compressor inlet and the compressor outlet. In addition, a measurement plane for microphone traverses was set to allow the evaluation of the sound field. The tests provided fundamental insight into the main noise sources and the structure of the sound field at the inlet and the outlet of a high speed compressor stage.

2P1-C03 Real-time Flow Measurement using High Speed Vision

2007 ◽  
Vol 2007 (0) ◽  
pp. _2P1-C03_1-_2P1-C03_2
Author(s):  
Taku TANIGUCHI ◽  
Kenkichi YAMAMOTO ◽  
Idaku ISHII
Keyword(s):  
Real Time ◽  
Flow Measurement ◽  
High Speed ◽  
Time Flow
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