Numerical Study of Reduced Frequency Effect on Longitudinal Stability Derivatives of Airfoil under Pitching and Plunging Oscillations

Esfahani, Vahid Nasr; Mani, Mahmoud

doi:10.5028/jatm.v8i3.647

Cited by 2 publications

(2 citation statements)

References 2 publications

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“…Unsteady aerodynamics is related to a series of time sequence data with time delay effects. 15 The long short-term memory network, which is a variant of the traditional recurrent neural network (RNN) by replacing traditional nodes in the hidden layer with computation units called memory cells, performs very well in sequence prediction and has become one of the most popular deep learning architectures. 32 LSTM networks are able to overcome traditional difficulties that result from too large or too small gradient values.…”

Section: Computation Schemementioning

confidence: 99%

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Aerodynamic surrogate model based on deep long short-term memory network: An application on high-lift device control

Zhang

Wang

Sun

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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An unsteady aerodynamic surrogate model based on the deep LSTM (long short-term memory) network is proposed for predicting unsteady aerodynamic coefficients. Deflection angles and deflection velocities of control surfaces are introduced to input values of the surrogate model to enhance the capability of identifying different motion states so that accumulative error can be controlled. Longitudinal stability is extremely important for flight safety while few studies have worked on unsteady aerodynamics of airfoils/wings with moving high-lift device (HLD) motion. Longitudinal static margin sequence of the HLD extending process is studied, and nonlinearity and hysteresis of coefficients in HLD motion are validated. The surrogate model is then applied in HLD motion control with the particle swarm optimization (PSO) method. Additionally, the results are then performed in three-dimensional aircraft HLD control. Validation computations show that longitudinal stability of optimized configuration is promoted with lift coefficient unchanged.

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Section: Computation Schemementioning

confidence: 99%

“…The results show that reduced frequency is related positively with stability in plunging oscillation. 15 Thus, the move of control surfaces may bring non-negligible unsteady effect. In this study, control surfaces of the HLD move with time, and moving parameters are studied.…”

Section: Introductionmentioning

confidence: 99%