Heather Kline


Ph.D. Candidate, Aeronautics and Astronautics, Stanford University, 2013-Present.
M.S., Aeronautics and Astronautics, Stanford University, 2013.
B.S., Dual Aerospace Engineering and Mechanical Engineering, Rensselaer Polytechnic Institute, 2011.

Research Interests

My research is in the robust optimization of hypersonic vehicles for access to space. Hypersonic airbreathing vehicles will make access to space more economical through decreasing the oxidizer which needs to be carried in the overall launch system and facilitation airline-like operations. The objective of this research is to develop and improve on methods of robust simulation-based design for hypersonic vehicles incorporating uncertainties, multiphysics simulation, and multidisciplinary design objectives. I am using inlet-forebody mold lines of a hypersonic airbreathing launch vehicle as the design problem, and utilizing adjoint methods to compute gradients. I am also a developer for the open-source CFD suite SU2 . Robust optimization requires that a design not only meet constraints and maximize performance, but also that the design operates well at off-design conditions. This is especially relevant to scramjets for access to space as the vehicles encouter an extremely wide range of conditions while accelerating and as some scramjets designs are extremely sensitive to small geometry changes.

My research interests include:

  • Robust optimization and design under uncertainty.
  • Shape deformations of slender hypersonic vehicles.
  • Fluid-structure interactions.
  • Adjoint-based design.

Recent Work

Ongoing work includes the implementation of boundary conditions for the continuous adjoint of arbitrary functions at an outlet, as well as other objective functions. I am also working on interpolation between dissimilar structural and fluid meshes to facilitate coupled aerostructural simulation. These tools will facilitate efficient multidisciplinary optimization of hypersonic engine inlets.

A REST-class inlet, results from "Sensitivity of the Performance of a 3-Dimensional Hypersonic Inlet to Shape Deformations" .

Adjoint solution for mass flow rate, 2-dimensional inlet optimized at Mach 5.0.

Flow solution for the same 2-dimensional inlet optimized for mass flow rate at Mach 5.0.


Kline, H.L., Palacios, F., Alonso, J.J., "Sensitivity of the Performance of a 3-Dimensional Hypersonic Inlet to Shape Deformations," 19th AIAA International Space Planes and Hypersonic Systems and Technologies Conference, AIAA Paper 2014-3228, Atlanta, GA, June 2014.
Kline, H.L, Palacios, F., Economon, T.D., and Alonso, J.J. "Adjoint-Based Optimization of a Hypersonic Inlet." 22nd AIAA Computational Fluid Dynamics Conference, AIAA Paper 2015-3060, Dallas, TX, June 2015
Kline, H.L., Economon, T.D., Alonso, J.J., "Multi-Objective Optimization of a Hypersonic Inlet Using Generalized Outflow Boundary Conditions in the Continuous Adjoint Method," 54th AIAA Aerospace Sciences Meeting, AIAA Paper 2016-0912, San Diego, CA, January 2016.
This work was supported by a NASA Space Technology Research Fellowship.