Multi-rotor wake propagation investigation for atmospheric sampling

2019 ◽  
Author(s):  
Glen Throneberry ◽  
Christopher M. Hocut ◽  
Fangjun Shu ◽  
Abdessattar Abdelkefi
Keyword(s):  
Rotor Wake ◽  
Atmospheric Sampling

scholarly journals Assessing recent measurement techniques for quantifying black carbon concentration in snow

2012 ◽  
Vol 5 (3) ◽  
pp. 3771-3795 ◽  
Author(s):  
J. P. Schwarz ◽  
S. J. Doherty ◽  
F. Li ◽  
S. T. Ruggiero ◽  
C. E. Tanner ◽  
...  
Keyword(s):  
Black Carbon ◽  
Single Particle ◽  
Carbon Concentration ◽  
Mass Concentration ◽  
Measurement Techniques ◽  
Integrating Sphere ◽  
Recent Measurement ◽  
Atmospheric Sampling ◽  
Careful Assessment ◽  
Snow Samples

Abstract. We evaluate the performance of the Single Particle Soot Photometer (SP2) and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW) in quantifying the concentration of refractory black carbon (BC) in snow samples. We find that the SP2 can be used to measure BC mass concentration in snow with substantially larger uncertainty (60%) than for atmospheric sampling (<30%). Achieving this level of accuracy requires careful assessment of nebulizer performance and SP2 calibration with consideration of the fact that BC in snow tends to larger sizes than typically observed in the atmosphere. Once these issues are addressed, the SP2 is able to measure the size distribution and mass concentration of BC in the snow. Laboratory comparison of the SP2 and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW) revealed significant biases in the estimate of BC concentration from the ISSW when test samples contained dust or non-absorbing particulates. These results suggest that current estimates of BC mass concentration in snow and ice using either the SP2 or the ISSW may be associated with significant underestimates of uncertainty.

Calibration of a cyclone separator for atmospheric sampling

1987 ◽  
Vol 65 ◽  
pp. 261-266 ◽  
Author(s):  
Seshasayi Dharmavaram ◽  
Philip K. Hopke
Keyword(s):  
Cyclone Separator ◽  
Atmospheric Sampling

Unsteady Numerical Simulation of Shock Systems in Vaneless Counter-Rotating Turbine

2005 ◽  
Author(s):  
Huishe Wang ◽  
Qingjun Zhao ◽  
Xiaolu Zhao ◽  
Jianzhong Xu
Keyword(s):  
Numerical Simulation ◽  
Mach Number ◽  
Leading Edge ◽  
Turbine Rotor ◽  
Nozzle Design ◽  
Suction Surface ◽  
Rotor Wake ◽  
Wake Interaction ◽  
Unsteady Numerical Simulation ◽  
Almost All

A detailed unsteady numerical simulation has been carried out to investigate the shock systems in the high pressure (HP) turbine rotor and unsteady shock-wake interaction between coupled blade rows in a 1+1/2 counter-rotating turbine (VCRT). For the VCRT HP rotor, due to the convergent-divergent nozzle design, along almost all the span, fishtail shock systems appear after the trailing edge, where the pitch averaged relative Mach number is exceeding the value of 1.4 and up to 1.5 approximately (except the both endwalls). A group of pressure waves create from the suction surface after about 60% axial chord in the VCRT HP rotor, and those waves interact with the inner-extending shock (IES). IES first impinges on the next HP rotor suction surface and its echo wave is strong enough and cannot be neglected, then the echo wave interacts with the HP rotor wake. Strongly influenced by the HP rotor wake and LP rotor, the HP rotor outer-extending shock (OES) varies periodically when moving from one LP rotor leading edge to the next. In VCRT, the relative Mach numbers in front of IES and OES are not equal, and in front of IES, the maximum relative Mach number is more than 2.0, but in front of OES, the maximum relative Mach number is less than 1.9. Moreover, behind IES and OES, the flow is supersonic. Though the shocks are intensified in VCRT, the loss resulted in by the shocks is acceptable, and the HP rotor using convergent-divergent nozzle design can obtain major benefits.

Summary of the interaction of a rotor wake with a circular cylinder

AIAA Journal ◽  
1995 ◽  
Vol 33 (3) ◽  
pp. 470-478 ◽  
Author(s):  
J. M. Kim ◽  
N. M. Komerath
Keyword(s):  
Circular Cylinder ◽  
Rotor Wake

Rotor Wake Modeling for Flight Dynamic Simulation of Helicopters

AIAA Journal ◽  
10.2514/2.922 ◽  
2000 ◽  
Vol 38 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Richard E. Brown
Keyword(s):  
Dynamic Simulation ◽  
Rotor Wake ◽  
Wake Modeling

scholarly journals Experimental investigation of main rotor wake

2017 ◽  
Vol 115 ◽  
pp. 02013 ◽  
Author(s):  
Robert Stepanov ◽  
Sergey Mikhailov
Keyword(s):  
Experimental Investigation ◽  
Main Rotor ◽  
Rotor Wake
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