Variations in the Eddy‐Convection Speeds in Rocket‐Exhaust Flows and Their Influence on the Radiated Noise

1963 ◽  
Vol 35 (11) ◽  
pp. 1913-1914
Author(s):  
John E. Ffowcs‐Williams
Keyword(s):  
Radiated Noise ◽  
Rocket Exhaust

EFFECT OF FLIGHT AND MOTOR OPERATING CONDITIONS ON INFRARED SIGNATURE PREDICTIONS OF ROCKET EXHAUST PLUMES

2015 ◽  
Vol 14 (1) ◽  
pp. 29-56 ◽  
Author(s):  
Robert Stowe ◽  
Sophie Ringuette ◽  
Pierre Fournier ◽  
Tracy Smithson ◽  
Rogerio Pimentel ◽  
...  
Keyword(s):  
Operating Conditions ◽  
Exhaust Plumes ◽  
Infrared Signature ◽  
Rocket Exhaust

Modeling Vibration-Induced Tire-Pavement Interaction Noise in the Mid-frequency Range

2020 ◽  
Author(s):  
Sterling McBride ◽  
Ricardo Burdisso ◽  
Corina Sandu
Keyword(s):  
Sound Intensity ◽  
Element Model ◽  
Dominant Frequency ◽  
Contact Forces ◽  
Surface Velocity ◽  
New Wave ◽  
Normal Surface ◽  
Radiated Noise ◽  
Physical Effects ◽  
Effects Of Rotation

ABSTRACT Tire-pavement interaction noise (TPIN) is one of the main sources of exterior noise produced by vehicles traveling at greater than 50 kph. The dominant frequency content is typically within 500–1500 Hz. Structural tire vibrations are among the principal TPIN mechanisms. In this work, the structure of the tire is modeled and a new wave propagation solution to find its response is proposed. Multiple physical effects are accounted for in the formulation. In an effort to analyze the effects of curvature, a flat plate and a cylindrical shell model are presented. Orthotropic and nonuniform structural properties along the tire's transversal direction are included to account for differences between its sidewalls and belt. Finally, the effects of rotation and inflation pressure are also included in the formulation. Modeled frequency response functions are analyzed and validated. In addition, a new frequency-domain formulation is presented for the computation of input tread pattern contact forces. Finally, the rolling tire's normal surface velocity response is coupled with a boundary element model to demonstrate the radiated noise at the leading and trailing edge locations. These results are then compared with experimental data measured with an on-board sound intensity system.

Compact Energy Measuring System for Short Pulse Lasers

2013 ◽  
Vol 20 (2) ◽  
pp. 183-190 ◽  
Author(s):  
A. Barna ◽  
I. B. Földes ◽  
Z. Gingl ◽  
R. Mingesz
Keyword(s):  
Short Pulse ◽  
Electronic Devices ◽  
Laser Pulses ◽  
Measuring System ◽  
Electric Response ◽  
Usb Interface ◽  
Radiated Noise ◽  
Fiber Optical ◽  
Measurement Control ◽  
Short Pulse Lasers

Abstract In experiments with short-pulse lasers the measurement control of the energy of the laser pulse is of crucial importance. Generally it is difficult to measure the amplitude of the pulses of short-pulse lasers using electronic devices, their response time being longer than the duration of the laser pulses. The electric response of the detector is still too fast to be directly digitized therefore a peak-hold unit can be used to allow data processing for the computer. In this paper we present a device which measures the energy of UV short (fs) pulses shot-byshot, digitizes and sends the data to the PC across an USB interface. The circuit is based on an analog peak detect and hold unit and the use of fiber optical coupling between the PC and the device provides a significant improvement to eliminate potential ground loops and to reduce conductive and radiated noise as well. The full development is open source and has been made available to download from our web page (http://www.noise.inf.u-szeged.hu/Instruments/PeakHold/).

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