The application of a transient testing method to the determination of acoustic properties of unknown systems

1980 ◽  
Vol 71 (4) ◽  
pp. 545-554 ◽  
Author(s):  
C.W.S. To ◽  
A.G. Doige
Keyword(s):  
Acoustic Properties ◽  
Testing Method

A Numerical Investigation of Aeroacoustic Fan Blade Flutter

2003 ◽  
Author(s):  
X. Wu ◽  
M. Vahdati ◽  
A. I. Sayma ◽  
M. Imregun
Keyword(s):  
Research Effort ◽  
Pressure Rise ◽  
Acoustic Properties ◽  
Pressure Amplitude ◽  
Ongoing Research ◽  
Blade Flutter ◽  
Fan Blade ◽  
Underlying Mechanisms ◽  
Flutter Margin

This paper reports the results of an ongoing research effort to explain the underlying mechanisms for aeroacoustic fan blade flutter. Using a 3D integrated aeroelasticity method and a single passage blade model that included a representation of the intake duct, the pressure rise vs. mass flow characteristic of a fan assembly was obtained for the 60%–80% speed range. A novel feature was the use of a downstream variable-area nozzle, an approach that allowed the determination of the stall boundary with good accuracy. The flutter stability was predicted for the 2 nodal diameter assembly mode arising from the first blade flap mode. The flutter margin at 64% speed was predicted to drop sharply and the instability was found to be independent of stall effects. On the other hand, the flutter instability at 74% speed was found to be driven by flow separation. Further post-processing of the results at 64% speed indicated significant unsteady pressure amplitude build-up inside the intake at the flutter condition, thus highlighting the link between the acoustic properties of the intake duct and fan blade flutter.

Comparison of Optical Smoke Density of Expanded Polystyrene without and with Cover Components Used in ETICS

2013 ◽  
Vol 724-725 ◽  
pp. 1625-1629
Author(s):  
Peter Rantuch ◽  
Tomáš Chrebet ◽  
Karol Balog
Keyword(s):  
Thermal Radiation ◽  
Optical Density ◽  
Glass Fibre ◽  
Expanded Polystyrene ◽  
Composite Systems ◽  
Testing Method ◽  
Potential Source ◽  
Smoke Generation ◽  
Pilot Burner

This paper deals with expanded polystyrene (EPS) as a potential source of smoke. We compared specific optical density of smoke from EPS and EPS strengthened by glass fibre mash and plaster which is used in external thermal insulation composite systems (ETICS). There was used testing method by ISO 5659 Plastics Smoke generation Part 2: Determination of optical density by a single-chamber test. The samples were exposed to a constant 50 kW.m-2 of thermal radiation. There was not used a pilot burner. During flame combustion samples evolved high amount of smoke. Samples from EPS released more smoke like samples with ETICS cover.

Measurement of Elastomer's Bulk Modulus by Means of a Confined Compression Test

1994 ◽  
Vol 67 (5) ◽  
pp. 871-879 ◽  
Author(s):  
Shu H. Peng ◽  
Takao Shimbori ◽  
Akbar Naderi
Keyword(s):  
Bulk Modulus ◽  
Volume Change ◽  
Treatment Technique ◽  
Pressure Loading ◽  
Confined Compression ◽  
Routine Test ◽  
Simple Method ◽  
Testing Method ◽  
Analysis Technique

Abstract The bulk modulus represents a material's resistance to volume change when subjected to pressure loading. Determination of bulk modulus is important for evaluation of applications where compression is involved. Most methods proposed for this purpose are complicated and costly. A simple method is to compress an elastomer button, fully confined in a metal fixture, on a tensile/compression machine. The reliability of this method is studied and a data-treatment technique is proposed to improve the accuracy. It shows that the testing method, with the new analysis technique recommended, is efficient and can be used as a routine test.

scholarly journals Determination Of Thermal Parameters Of Solar Water Heating Collectors Using The “Dark” Testing Method

2020 ◽  
Vol 02 (11) ◽  
pp. 62-67
Author(s):  
Nizomjon Orifovich Usmonov ◽  
◽  
Xayrulla Sunnatullaevich Isakhojaev ◽  
Saodat Rakhsulaevna Akhmatova ◽  
Feruza Abdullaevna Khoshimova ◽  
...  
Keyword(s):  
Thermal Characteristics ◽  
Hot Water ◽  
Thermal Testing ◽  
Water Heating ◽  
Solar Water Heating ◽  
Solar Water ◽  
Testing Method ◽  
Hot Water Supply ◽  
Hot Water Supply System

In the production of flat solar water heating collectors, thermal testing occupies a special place, the purpose of which is to determine their thermal characteristics experimentally. The corresponding approximation expressions are proposed for determining the coefficient of heat loss, inclined to the horizon at an angle of 300 for the average conditions of their operation in the hot water supply system

Experimental determination of the electro-acoustic properties of thin film AlScN using surface acoustic wave resonators

2019 ◽  
Vol 126 (7) ◽  
pp. 075106 ◽  
Author(s):  
Nicolas Kurz ◽  
Anli Ding ◽  
Daniel F. Urban ◽  
Yuan Lu ◽  
Lutz Kirste ◽  
...  
Keyword(s):  
Thin Film ◽  
Acoustic Wave ◽  
Experimental Determination ◽  
Surface Acoustic Wave ◽  
Acoustic Properties ◽  
Acoustic Wave Resonators

Method for Determination of Operating Temperature of Building Photovoltaic Module

2013 ◽  
Vol 591 ◽  
pp. 334-337
Author(s):  
Chen Guang Wei ◽  
Yi Wang Bao ◽  
Xiao Ying Deng ◽  
Liang Jiang
Keyword(s):  
Operating Temperature ◽  
Test Methods ◽  
National Standard ◽  
Photovoltaic Module ◽  
Operation Condition ◽  
Testing Method ◽  
Optimal Load ◽  
Building Integrated Photovoltaic ◽  
Load Resistor

There is no national standard and international standard about nominal module operating temperature (NMOT) test methods for Building Integrated Photovoltaic (BIPV) modules. An in-lab testing method for measuring NMOT of BIPV modules is proposed. Based on the real operation condition of solar cell, the effect of ambient temperature, wind speed and optimal load resistor to operating temperature were analyzed. The surface temperature, interior temperature and back temperature of BIPV module were measured and the NMOT was determined.

Verification of Methods Used for Fatigue Testing of Small Steel Specimens Taken from Existing Structures

2016 ◽  
Vol 250 ◽  
pp. 232-237
Author(s):  
Tomasz Tomaszewski ◽  
Janusz Sempruch ◽  
Przemysław Strzelecki
Keyword(s):  
Fatigue Testing ◽  
Experimental Tests ◽  
Fatigue Tests ◽  
Steel Plates ◽  
Existing Structures ◽  
Testing Method ◽  
Standard Specimens ◽  
Different Thickness ◽  
Small Steel

This paper presents results of fatigue tests performed on standard specimens and minispecimens taken from two EN 1.4301 acid-resistant steel plates of different thickness. The tests were required for determination of the state of vibrating machines made from the same material. The results confirmed that the proposed testing method can be used for experimental tests.

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