Systems Engineering and Multidisciplinary Design Optimization Commons^™

Investigating The Numerical Stability Of Using An Impedance Boundary Condition To Model Broadband Noise Scattering With Acoustic Liners, Michelle E. Rodio, Fang Q. Hu, Douglas M. Nark

Mathematics & Statistics Faculty Publications

Reducing aircraft noise is a major objective in the field of computational aeroacoustics. When designing next generation quiet aircraft, it is important to be able to accurately and efficiently predict the acoustic scattering by an aircraft body from a given noise source. Acoustic liners are an effective tool for achieving aircraft noise reduction and are characterized by a frequency-dependent impedance value. Converted into the time-domain using Fourier transforms, an impedance boundary condition can be used to simulate the acoustic wave scattering by geometric bodies treated with acoustic liners. A Broadband Impedance Model will be discussed in which the liner impedance …

Satellite Constellation Deployment And Management, Joseph Ryan Kopacz

Electronic Theses and Dissertations

This paper will review results and discuss a new method to address the deployment and management of a satellite constellation. The first two chapters will explorer the use of small satellites, and some of the advances in technology that have enabled small spacecraft to maintain modern performance requirements in incredibly small packages.

The third chapter will address the multiple-objective optimization problem for a global persistent coverage constellation of communications spacecraft in Low Earth Orbit. A genetic algorithm was implemented in MATLAB to explore the design space – 288 trillion possibilities – utilizing the Satellite Tool Kit (STK) software developers kit. …

Identify Aerodynamic Derivatives Of The Airplane Attitude Channel Using A Spiking Neural Network, Nguyen Quang Vinh, Nguyen Duc Thanh, Hoang Minh Dac, Truong Dang Khoa

International Journal of Aviation, Aeronautics, and Aerospace

The paper proposes a method for identifying aerodynamic coefficient derivatives of aircraft attitude channel using spiking neural network (SNN) and Gauss-Newton algorithm based on data obtained from actual flights. Using SNN combination with Gauss-Newton iterative calculation algorithm allows the identification of aerodynamic coefficient derivatives in a nonlinear model for aerodynamic parameters with higher accuracy and faster calculation time. The paper proposes an algorithm to train the SNN multi-layer network by Normalized Spiking Error Back Propagation (NSEBP), in which, in the forward propagation period, the time of output spikes is calculating by solving quadratic equations instead of detection by traditional methods. …

Low Thrust And Low Power Propulsion Systems Options For Small Satellites, Redha Amri

International Journal of Aviation, Aeronautics, and Aerospace

The present work focuses on the study of low thrust propulsion systems. Cold gas, thermal and monopropellant systems with a blow down depressurisation mode have been taken in consideration in this study. Most of propellants that can be used for small satellite propulsion systems were selected here in order to give the propulsion engineer many propellant options with a good idea about the performance of each propellant, and this is important to make a good trade-off during the system design. For cold gas and thermal propulsion, the propellants taken into account in this study are: Oxygen (O2), Nitrogen (N2), Hydrogen …