Aerothermodynamic Shape Optimization of Reentry Capsule

2018-06-25
Kutkan, Halit
Eyi, Sinan
This paper presents a hybrid method based on proper orthogonal decomposition (POD) with a trained radial basis function (RBF) network, on direct simulation monte carlo (DSMC) solutions for aerothermodynamic front surface optimization of Stardust reentry. Gaussian and multiquadric RBFs are implemented for comparison, and multiquadric functions are chosen due to their insensitivity to diverse shape parameters. Cubic uniform B-spline curves are used innovatively for parameterization of the geometry change,instead of curve fitting the geometry itself. This makes possible to reduce the number of design variables. Gradientbased optimization strategy is implemented by regarding the distributions of pressure, shear stress and heat flux along the surface of the geometries. G.A. Bird’s two dimensional axisymmetric DSMC solver [1]is used as the physics solver, and 11 species air model are chosen with 41 chemical reactions according to atmospheric conditions of the reentry. Different geometries are obtained via deviatingthe design variables arbitrarily to form a snapshot pool. In this manner, the approximation success of the POD-RBF methodology is tested on highly nonlinear flow conditions with arbitrarily chosen design of experiment. Finally, the optimized geometries are simulated via DSMC code and the solutions are compared with the solutions of POD-RBF network. Method loweredthe optimization time extraordinarily and provided satisfactory results.

Suggestions

Aerothermodynamic Shape Optimization of Reentry Capsules Using DSMC and POD Methods
Kutkan, Halit; Eyi, Sinan (null; 2018-07-09)
This paper presents a hybrid method based on proper orthogonal decomposition (POD) with a trained radial basis function (RBF) network, on direct simulation monte carlo (DSMC) solutions for aerothermodynamic front surface optimization of Stardust re-entry. Gaussian and multiquadric RBFs are implemented for comparison, and multiquadric functions are chosen due to their insensitivity to diverse shape parameters. Cubic uniform B-spline curves are used ...
Aerothermodynamic shape optimization using DSMC and POD-RBF methods
Kutkan, Halit; Eyi, Sinan; Department of Aerospace Engineering (2018)
This thesis study presents a hybrid method based on Proper Orthogonal Decomposition (POD) with Radial Basis Function (RBF), on Direct Simulation Monte Carlo (DSMC) solutions for aerothermodynamic front surface optimization of Stardust re-entry. Gaussian and multiquadric RBFs are implemented for comparison, and multiquadric functions are chosen due to their insensitivity to diverse shape parameters. Cubic uniform B-spline curves are used innovatively for parameterization of the geometry change, instead of cu...
Numerical investigation of solidification
Alrmah, Masoud; Dursunkaya, Zafer; Department of Mechanical Engineering (2005)
Finite element solution of solidification process in 2-D Cartesian and axisymmetric geometries is investigated. The use of finite element may result in spurious increase of temperature in the field and the selection of the mushy zone range when used as a numerical tool along with the selection of the mesh size results in large errors in the predicted solidification time. The approach works best for problems where the mushy zone range is finite and the thermal conductivities of both phases are high.
Optimized Electromagnetic Harvester with a Non-Magnetic Inertial Mass
Ulusan, Hasan; Yasar, Oguz; Zorlu, Ozge; Külah, Haluk (2015-09-09)
This paper presents an optimization study to decrease the operation frequency and increase the output power of a miniature electromagnetic (EM) energy harvester, by incorporating a non-magnetic inertial mass together with the moving magnet. The harvester coil position has been optimized through FEM, and validated through tests. Experimental studies on the inertial mass showed that increasing the magnet size further increases the resonance frequency due to the increased magnetic forces. Conversely, using a n...
Properties of BaYO3 perovskite and hydrogen storage properties of BaYO3Hx
Gencer, Ayşenur; Surucu, Gokhan (Elsevier BV, 2020-03-27)
In this study, Density Functional Theory (DFT) calculations have been performed for BaYO3 perovskite with the generalized gradient approximation (GGA) as implemented in Vienna Ab-initio Simulation Package (VASP). The structural optimization of BaYO3 perovskite have been studied for the five possible phases: cubic, tetragonal, hexagonal, orthorhombic and rhombohedral to determine the most stable phase of BaYO3 perovskite. It has been found that the cubic phase is the most stable one and electronic and mechan...
Citation Formats
H. Kutkan and S. Eyi, “Aerothermodynamic Shape Optimization of Reentry Capsule,” 2018, vol. 2018, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/45991.