Wind Tunnel Test

The Aerodynamics in Sports project is a three year cooperative agreement between NASA Ames (Learning Technology Project) and Cislunar Aerospace, Inc. (NCC2-9014). The emphasis of this project is tennis. The project team is composed of aerospace engineers from CAI, NASA engineers, and sports scientists from the US Tennis Association (the governing board in the United States for tennis) and other organizations.

Elementary, middle and high school students are lead through the scientific method and learn how an actual research project is conducted. As the research team learns and progresses, team reports and classroom instructional materials are posted on our WWW site (http://wings.avkids.com/Tennis). The team conducts real-time Web chats and Internet video conferences. The subject of one of the video conferences is wind tunnel testing and computational fluid dynamics. One of the benefits for students is that sports are a natural attention grabber and for the elementary and middle school teachers the tennis ball is a familiar and "less scary" object to study then an aircraft or airfoil and yet the same aerodynamic principles can be discussed.

The team is studying ball aerodynamics (including velocity, acceleration, spin), ball/court interaction and biomechanics. The team was a guest at the 1997 U.S. Open where ball spin and player biomechanics data was collected and has been invited back in 1998. A high speed digital camera was used to collect the information.

At each step the goal is to showcase aerodynamics concepts and the work of NASA. A major educational component of this project is to demonstrate how wind tunnel experiments and CFD simulations are used together to calculate aerodynamic forces. Thus, the team has planned to conduct wind tunnel tests that would be used in conjunction with the CFD simulations CAI and Shishir Pandya of NASA Ames Applied Aerodynamics branch (Dr. Dochan Kwak's branch) have been creating.

Since our project is oriented towards elementary and middle school students, the most effective presentation of flow visualization in is a smoke flow visualization test and a demonstration of how spin is generated in a sports ball within a wind tunnel. Visualization of the flow separation, the burbling effects of turbulence, transition from laminar to turbulence, and any visible wake would make a meaningful demonstration of these concepts for the younger students.

In the following pages, the calculations of the wind tunnel speeds needed, rotational speeds required, force calculations, and a description of the mount and ball are presented.