Engineering Grant Proposal Technical Writing

Grant Proposal for Aerospace Research: The Development of Analytical Models for Shock Induced Boundary Layer Separation

For the completion of the final project in the Editing for Publication course, I will be submitting a grant proposal, written on behalf of a private individual who has developed a theoretical model that accurately predicts airflow patterns on aircraft and missile control surfaces. This project will ultimately be submitted to the  U.S. Air Force Office of Scientific Research’s (AFSOR) Air Force Research Laboratory, as a response to the AFSOR’s Broad Agency Announcement (BAA), “High-Speed Aerodynamics”.

The proposed model deals with airflow patterns on control surfaces in high speed flight. As an aircraft approaches hypersonic speeds, surface protuberances or other flow disturbances can create adverse pressure gradients which can cause airflow boundary layers to separate from the surface. As these boundary layers reattach to the surface of the aircraft, high pressure and heat transfer loads are generated, which can cause catastrophic failure in the structural component of the craft. Predicting the behavior of airflow on control surfaces has been a major concern since the development of hypersonic vehicles but a complete understanding of the phenomenon has remained elusive to researchers since the 1970’s.

Flow Separation Resulting form Shockwave Boundary Layer Interactions

In order to gain a better understanding of flow separation, engineers have attempted to reproduce the phenomena through wind tunnel testing. From these tests, researchers have been able to produce empirical some models, but have failed to provide a full understanding of the physical principles behind the behavior. With advancements in technology, researchers have been able to achieve some progress, but currently, there is no accurate way by which separated flow patterns can be fully developed.

A hypersonic vehicle in the Arnold Engineering Development Complex Hypervelocity Wind Tunnel. (U.S. Air Force photo/Mike Smith)

My client has proposed that in order to accurately predict these patterns, advanced analytical models, should be developed. He has created an analytical model which has been able to accurately predict separation shock patterns. What makes this model unique is that it was developed from preliminary studies that defined airflow regions by the same fluid dynamic principles – something that Air Force engineers have not attempted. This model also differs from previous models because it has the ability to be applied to specific conditions in flight that cannot be duplicated in wind tunnels.

Results of preliminary tests using this theoretical model have been successfully correlated with the results of wind tunnel testing. Based upon results in these areas, my client believes that with further research and testing more aspects of boundary layer separation can be accurately predicted.

For the research proposal, I plan on discussing the research history of boundary layer separation and how previous testing has failed to produce the required results. And then, I will highlight the limitations of this research and make the argument that analytical methods should be utilized to solve the problem.

The main focus of the proposal will be a discussion of the analytical method that my client has developed. I plan to illustrate the correlation between the results of the analytical method and the results that have been produced by Air Force wind tunnel testing. I plan to then outline the specific objectives that my client is hoping to achieve within the proposed research period.

As I continue to research and study this issue, I am convinced of its importance within the future of defense work. The development of theoretical models that will accurately predict wind tunnel test results will be an asset to the U.S. Air Force and the further development of aircraft and missile defense.

Image sources:

Smith. M. (2014). [Photograph of a Hypersonic Vehicle in Wind Tunnel]. Retrieved from

[Schematic Illustration of Shockwave Boundary Layer Interactions]. (2014) Retrieved from