• Dr. John Vassberg
  • The Boeing Company
  • 104D Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Pradeep Raj

Aerodynamic characteristics and flight dynamics of boomerangs are investigated.  A basic aerodynamic model, developed in the 1960’s, is expanded upon using Blade Element Theory.  The new aerodynamic model is coupled with a gyroscope model for rudimentary analyses.  Some significant findings are made regarding the radius of a boomerang’s circular flight path, the required inclination angle of its axis-of-rotation, its trim state, as well as its dynamic stability.  These discoveries provide a basic understanding of how the interplay between aero-dynamic forces and moments, and gyroscopic precession combine to return the boomerang to its rightful owner by way of a circular flight path.

A traditional V-shaped boomerang design is developed as a case study for further detailed analyses.  Unsteady Reynolds-averaged Navier-Stokes solutions provide accurate aerodynamic characteristics of the subject boomerang.  The high-fidelity aerodynamic model is coupled with the equations of motion to provide accurate six-degree-of-freedom simulations of boomerang flight dynamics.  Boomerang orientation during its flight trajectory is described by the classical Euler angles.

Biography:

Dr. Vassberg is the Lead Aerodynamicist and Engineer of the BCA Design Center in Southern California. Prior to this, he was Chief Aerodynamicist of Boeing’s Research & Technology organization.  He is a Boeing Technical Fellow, an AIAA Fellow, and recipient of the AIAA Aerodynamics Award in 2012.  Dr. Vassberg actively supports various BCA, BDS and BR&T airplane design programs.  He was chief aerodynamicist of the recently-completed Advanced Joint Air Combat System (AJACS), Speed-Agile Configuration Development (SACD) and Over-Wing Nacelle (OWN) programs.  [The SACD Program won the 2013 Aviation Week Laureate Award in the Aero and Propulsion category.]

Dr. Vassberg joined Boeing (McDonnell Douglas Corp) in 1982, working in the Aerodynamic Technology Programs group, where he developed or co-developed transonic airfoil technologies such as optimum upper-surface pressure recovery paths, divergent trailing edge and trailing-edge wedge concepts, using computational methods and validating these technology advancements with wind tunnel testing.  Since then, Dr. Vassberg has developed, matured, transitioned, and applied numerous computational fluid dynamics (CFD) methods and aerodynamic technologies.  In order to accomplish this, he has worked about half of his career in aerodynamic research and technology groups and the other half in aircraft program development organizations.  During his 32 year career at Boeing, Dr. Vassberg has continuously engaged and collaborated with NASA Ames and Langley Research Centers, the Air Force Research Laboratory, the Naval Research Laboratory, as well as with various academic institutions.  He is considered a world authority in the development and application of CFD and aerodynamic shape optimization for aerodynamic design within an aircraft design environment.  Dr. Vassberg is chairman and a charter member of the International AIAA CFD Drag Prediction Workshop (DPW) organizing committee; he is also on the Advisory Board for the AIAA High-Lift Prediction Workshop.  Aircraft Programs that he has worked on or supported include:  AJACS, C-17, KC-10, MD-11, MD-12, MD-XX, MD-80, MD-90, UHB, B787, B747, B777, B737, B767, B717, BWB, LCF, OAW, and HSCT. 

Dr. Vassberg holds over a dozen Patents related to aerodynamic technologies, and has authored over 100 publications.  In addition, Dr. Vassberg has introduced and developed new fields of numerical simulation including:  in-flight refueling hose-drogue dynamics, towed-decoy dynamics, fast surface-paneling techniques, and globally-elliptic meshing methods.

Dr. Vassberg received his PhD from the University of Southern California in 1992, and his MS and BS from Texas A&M University in 1981 and 1980, respectively, all in Aerospace Engineering.  He has also taught classes at the University of California, Irvine in the MAE Department.