Experimental-Based Unified Unsteady Nonlinear Aerodynamic Modeling For Two-Dimensional Airfoils

2015 ◽  
Author(s):  
Mohamed Y. Zakaria ◽  
Haithem E. Taha ◽  
Muhammad R. Hajj ◽  
Ahmed A. Hussein
Keyword(s):  
Two Dimensional ◽  
Aerodynamic Modeling ◽  
Nonlinear Aerodynamic

scholarly journals Real-Time Onboard Global Nonlinear Aerodynamic Modeling from Flight Data

2016 ◽  
Vol 53 (5) ◽  
pp. 1261-1297 ◽  
Author(s):  
Jay M. Brandon ◽  
Eugene A. Morelli
Keyword(s):  
Real Time ◽  
Flight Data ◽  
Aerodynamic Modeling ◽  
Nonlinear Aerodynamic

Nonlinear Aerodynamic Effects on Transonic Flap Buzz, Tail Flutter and Limit-Cycle Oscillations of Two-Dimensional Wing-Flap-Tail Configurations

2009 ◽  
Vol 25 (4) ◽  
pp. 451-463
Author(s):  
J.-C. Cheng
Keyword(s):  
Flow Regime ◽  
Limit Cycle ◽  
Transonic Flow ◽  
Large Amplitude ◽  
Two Dimensional ◽  
Limit Cycle Oscillations ◽  
Restoring Force ◽  
Tail Structure ◽  
Euler Solver ◽  
Nonlinear Aerodynamic

ABSTRACTThe transonic tail flutter and flap buzz under the wing-flap-tail configurations are analyzed utilizing a dynamic grid capability of unstructured Euler solver coupled with an appropriate aeroelastic solver. From the results, the presence of a forewing, either stationary or oscillating, has significant effect on the tail flutter characteristics. In particular, the tail motion may be in resonance with the oscillating wing before the onset of flutter, which is dangerous to the tail structure because of the large amplitude oscillations. Besides, a complicated aerodynamic and aeroelastic interference of the tail have been found due to the unsteady disturbance which is a strong variability of flow structure induced by the buzz of the flap. In the high transonic flow regime, the flap buzz with limit-cycle oscillations does occur, and the influence induced by the tail is not important. The increasing restoring force at the pivot where the flap joints with the wing will reduce the flap oscillations that improves the effect of the flap buzz.

Spectrophotometric measurements of objective-prism spectra

1966 ◽  
Vol 24 ◽  
pp. 118-119
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Progress Report ◽  
Two Dimensional ◽  
Objective Prism ◽  
Made In

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.

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