Siva Nadarajah

Background

Doctor of Philosophy
Department of Aeronautics and Astronautics, Stanford University (1998-2004)

Master of Science
Department of Aeronautics and Astronautics, Stanford University (1997-1998)

Bachelor of Science
Department of Aerospace Engineering, University of Kansas (1993-1997)
Department of Mathematics, University of Kansas (1993-1997)

Detail Curriculum Vitae / Resume (pdf)

Research Interests

I am currently a graduate student in the Aerospace Computing Laboratory of the Department of Aeronautics and Astronautics at Stanford University. My research is on aerodynamic shape optimization techniques based on control theory. The following list are my current research areas:

• Continuous and Discrete Adjoint.To study the trade-off between the complexity of the discretization of the adjoint equation for both the continuous and discrete approach, the accuracy of the resulting estimate of the gradient, and its impact on the computational cost to approach an optimum solution.

Nadarajah, Siva; Jameson, Antony, "A Comparison of the Continuous and Discrete Adjoint Approach to Automatic Aerodynamic Optimization," AIAA 38th Aerospace Sciences Meeting and Exhibit, AIAA-2000-0667, Reno, NV, January 2000. (pdf)

Nadarajah, Siva; Jameson, Antony, " Studies of the Continuous and Discrete Adjoint Approaches to Viscous Automatic Aerodynamic Shape Optimization," AIAA 15th Computational Fluid Dynamics Conference, AIAA-2001-2530, Anaheim, CA, June 2001. (pdf)

• Optimization of Unsteady Flows.To develop the unsteady adjoint equation. Optimal control of time dependent trajectories require the solution of the adjoint equation in reverse time from a final boundary condition. The research will produce unsteady adjoint algorithms for the optimization of a blade shape for a helicopter rotor to minimize the average drag over a complete revolution. Similar techniques can also be used to reduce radiated noise from aircraft engines.

Nadarajah, Siva; Jameson, Antony, " Optimal Control of of Unsteady Flows Using Time Accurate and Non-Linear Frequency Domain Methods," 9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization Conference, AIAA-2002-5436, Atlanta, GA, Sept. 2002.

• Adjoint Method for the Calculation of Remote Sensitivities.The goal is to develop a set of discrete adjoint equations and their corresponding boundary conditions in order to quantify the influence of geometry modifications on the pressure distribution at an arbitrary location within the domain of interest. Traditional adjoint implementations were aimed at reducing a cost function computed from the pressure distribution on the surface that is being modified. In this case, however, we would like to obtain sensitivity derivatives of pressure distributions that are not collocated at the points where the geometry is being modified. This type of sensitivity calculation has not been attempted before and will be necessary for a variety of problems including sonic boom minimization, inlet design, turbomachinery design, etc.

Nadarajah, Siva; Jameson, Antony; Alonso, Juan "An Adjoint Method for the Calculation of Non-Collocated Sensitivities in Supersonic Flow," First MIT Conference on Computational Fluid Dynamics, Cambridge, MA, June 2001 (pdf)

Nadarajah, Siva; Jameson, Antony; Alonso, Juan "An Adjoint Method for the Calculation of Remote Sensitivities in Supersonic Flow," AIAA 40th Aerospace Sciences Meeting and Exhibit, AIAA-2002-0261, Reno, NV, January 2002. (pdf)

Nadarajah, Siva; Jameson, Antony; Alonso, Juan, " Sonic Boom Reduction using an Adjoint Method for Complete Aircraft Configurations in Supersonic Flow," 9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization Conference, AIAA-2002-5547, Atlanta, GA, Sept. 2002.

Publications

2002

Nadarajah, Siva; Jameson, Antony; Alonso, Juan "An Adjoint Method for the Calculation of Remote Sensitivities in Supersonic Flow," AIAA 40th Aerospace Sciences Meeting and Exhibit, AIAA-2002-0261, Reno, NV, January 2002. (paper, presentation)

Nadarajah, Siva; Jameson, Antony, " Optimal Control of of Unsteady Flows Using Time Accurate and Non-Linear Frequency Domain Methods," 9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization Conference, AIAA-2002-5436, Atlanta, GA, Sept. 2002.

Nadarajah, Siva; Jameson, Antony; Alonso, Juan, " Sonic Boom Reduction using an Adjoint Method for Complete Aircraft Configurations in Supersonic Flow," 9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization Conference, AIAA-2002-5547, Atlanta, GA, Sept. 2002. (paper)

2001

Nadarajah, Siva; Jameson, Antony, " Studies of the Continuous and Discrete Adjoint Approaches to Viscous Automatic Aerodynamic Shape Optimization," AIAA 15th Computational Fluid Dynamics Conference, AIAA-2001-2530, Anaheim, CA, June 2001. (paper, presentation)

Nadarajah, Siva; Jameson, Antony; Alonso, Juan "An Adjoint Method for the Calculation of Non-Collocated Sensitivities in Supersonic Flow," First MIT Conference on Computational Fluid Dynamics, Cambridge, MA, June 2001 (paper)

2000

Nadarajah, Siva; Jameson, Antony, "A Comparison of the Continuous and Discrete Adjoint Approach to Automatic Aerodynamic Optimization," AIAA 38th Aerospace Sciences Meeting and Exhibit, AIAA-2000-0667, Reno, NV, January 2000. (paper)