Determination of dynamic stability derivatives using forced oscillation technique

2002 ◽  
Author(s):  
N. Alemdaroglu ◽  
I. Iyigun ◽  
M. Altun ◽  
H. Uysal ◽  
F. Quagliotti ◽  
...  
Keyword(s):  
Dynamic Stability ◽  
Forced Oscillation ◽  
Forced Oscillation Technique ◽  
Stability Derivatives

A modified forced oscillation technique for measurements of respiratory resistance

1977 ◽  
Vol 42 (4) ◽  
pp. 650-655 ◽  
Author(s):  
H. Aronsson ◽  
L. Solymar ◽  
J. Dempsey ◽  
J. Bjure ◽  
T. Olsson ◽  
...  
Keyword(s):  
Forced Oscillation ◽  
Signal To Noise Ratio ◽  
Optimization Technique ◽  
Forced Oscillation Technique ◽  
Respiratory Resistance ◽  
Asthmatic Children ◽  
The Difference ◽  
Resistance Value ◽  
Automated Determination

We present a modification of forced oscillation technique for automated determination of total respiratory resistance during inspiration. The modifications consist of a computerized signal averaging and an optimization technique in the assessment of the resistance value. Thereby a favorable signal-to-noise ratio is obtained, allowing very low superimposed pressure oscillations. The method is validated by comparison with a conventional esophageal balloon method, by estimating added mechanical resistances in healthy subjects and by measuring the effect of bronchodilation in asthmatic children. The coefficient of variation as obtained from day-to-day measurements was about 7%. Mechanical resistances, estimated as the difference in total resistance with and without external resistance, were within 7% of their values determined for the resistances alone. A significant decrease in resistance was obtained in each of the asthmatic children following bronchodilation.

scholarly journals Measurement of Dynamic Stability Derivatives of Tailless Lamda-shape UAV using Forced Oscillation Method

2016 ◽  
Vol 44 (7) ◽  
pp. 552-561
Author(s):  
Kwangjin Yang ◽  
Hyoungseog Chung ◽  
Donghyun Cho ◽  
Eunhye An ◽  
Joonsoo Ko ◽  
...  
Keyword(s):  
Dynamic Stability ◽  
Forced Oscillation ◽  
Stability Derivatives ◽  
Derivatives Of ◽  
Oscillation Method

Estimation and Separation of Longitudinal Dynamic Stability Derivatives with Forced Oscillation Method Using Computational Fluid Dynamics

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 354
Author(s):  
Nadhie Juliawan ◽  
Hyoung-Seog Chung ◽  
Jae-Woo Lee ◽  
Sangho Kim
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Dynamic Stability ◽  
Forced Oscillation ◽  
Harmonic Oscillation ◽  
Test Model ◽  
Pitching Moment ◽  
Stability Derivatives ◽  
Oscillation Modes ◽  
Oscillation Method

This paper focuses on estimating dynamic stability derivatives using a computational fluid dynamics (CFD)-based force oscillation method, and on separating the coupled dynamic derivatives terms obtained from the method. A transient RANS solver is used to calculate the time history of aerodynamic moments for a test model oscillating about the center of gravity, from which the coupled dynamic derivatives are estimated. The separation of the coupled derivatives term is carried out by simulating simple harmonic oscillation motions such as plunging motion and flapping motion which can isolate the pitching moment due to AOA rate (Cmα˙) and the pitching moment due to pitch rate (Cmq), respectively. The periodic motions are implemented using a CFD dynamic mesh technique with user-defined function (UDF). For the validation test, steady and unsteady simulations are performed on the Army-Navy Finner Missile model. The static aerodynamic moments and pressure distribution, as well as the coupled dynamic derivative results from the pitching oscillation mode, show good agreement with the previously published wind tunnel tests and CFD analysis data. In order to separate the coupled derivative terms, two additional harmonic oscillation modes of plunging and flapping motions are tested with the angle of attack variations from 0 to 85 degrees at a supersonic speed to provide real insight on the missile maneuverability. The cross-validation study between the three oscillation modes indicates the summation of the individual plunging and flapping results becoming nearly identical to the coupled derivative results from the pitching motion, which implies the entire set of coupled and separated dynamic derivative terms can be effectively estimated with only two out of three modes. The advantages and disadvantages of each method are discussed to determine the efficient approach of estimating the dynamic stability derivatives using the forced oscillation method.

scholarly journals Evaluation of the forced oscillation technique for the determination of resistance to breathing

1968 ◽  
Vol 47 (9) ◽  
pp. 2045-2057 ◽  
Author(s):  
Aron B. Fisher ◽  
Arthur B. DuBois ◽  
Richard W. Hyde
Keyword(s):  
Forced Oscillation ◽  
Forced Oscillation Technique
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