Engineering Commons^™

Ab Initio Based State Specific Modeling Of N2+O System, Han Luo

Open Access Theses

Nitrogen and atomic oxygen play an important role in high temperature gas systems. Their Zeldovich reaction product nitric oxide not only affects aerothermal loads and emissions of hypersonic vehicles, but also has the possibility to influence the efficiency of hypersonic propulsion. Atomic oxygen induced nitrogen dissociation is another reaction mechanism of the N2+O system. However, due to the difficulty of conducting ground tests, there are no experimental data for this reaction now. Thermo-chemical nonequilibrium could make the problem more difficult since experiments could only track macroscopic gas properties instead of internal energy distribution. On the other hand, current reaction and …

Applications Of The Homotopy Analysis Method To Optimal Control Problems, Shubham Singh

Open Access Theses

Traditionally, trajectory optimization for aerospace applications has been performed using either direct or indirect methods. Indirect methods produce highly accurate solutions but suer from a small convergence region, requiring initial guesses close to the optimal solution. In past two decades, a new series of analytical approximation methods have been used for solving systems of dierential equations and boundary value problems.

The Homotopy Analysis Method (HAM) is one such method which has been used to solve typical boundary value problems in nance, science, and engineering. In this investigation, a methodology is created to solve indirect trajectory optimization problems using the Homotopy …

Tadpole Orbits In The L4/L5 Region: Construction And Links To Other Families Of Periodic Orbits, Alexandre G. Van Anderlecht

Open Access Theses

The equations of motion in the Circular Restricted Three-Body Problem (CR3BP) allow five equilibrium solutions, that is, the Lagrange or libration points. Two of the five equilibrium solutions are the triangular or equilateral libration points, L4 and L 5. As the secondary gravitational body moves in its orbit about the larger mass, L4 and L5 lead and trail the secondary by 60 degrees, respectively. This investigation focuses on periodic solutions in the vicinity of the triangular libration points, specifically horseshoe and tadpole orbits. Horseshoe orbits are symmetric periodic solutions in the plane of primary motion encompassing both …

Feasibility Analysis Of Large Length-Scale Thermocapillary Flow Experiment For The International Space Station, Samantha Jean Alberts

Open Access Theses

The investigation of microgravity fluid dynamics emerged out of necessity with the advent of space exploration. In particular, capillary research took a leap forward in the 1960s with regards to liquid settling and interfacial dynamics. Due to inherent temperature variations in large spacecraft liquid systems, such as fuel tanks, forces develop on gas-liquid interfaces which induce thermocapillary flows. To date, thermocapillary flows have been studied in small, idealized research geometries usually under terrestrial conditions. The 1 to 3m lengths in current and future large tanks and hardware are designed based on hardware rather than research, which leaves spaceflight systems designers …