Smart materials for turbomachinery quieting

As part of the Defense Advanced Research Projects Agency (DARPA) SAMPSON (Smart Aircraft and Marine Projects Demonstration) program, a team has been developing and testing the use of smart materials for quieting turbomachinery. The team is composed of representatives from Pennsylvania State University, General Dynamics Electric Boat, GTE BBN Technologies, and the Naval Surface Warfare Center Carderock Division. Four concepts for quieting were proposed and wind tunnel testing, water tunnel testing, as well as computational fluid dynamic analysis were performed to down select two of the concepts for further consideration: protuberance and gap control. The wind tunnel testing was performed to determine the optimum shape of the protuberance. Water tunnel testing was performed at Pennsylvania State University/Applied Research Laboratory to establish the performance of the protuberance and gap control elements. Piezoelectric inchworm actuators, developed by Pennsylvania State University/Center for Acoustics and Vibration, were utilized for the evaluation of the two concepts. GTE BBN Technologies developed the control system simulation for the ultimate concept, and General Dynamics Electric Boat was responsible for hydrodynamic and hydroacoustic analysis. Naval Surface Warfare Center/Carderock Division performed hydrodynamic analysis and developed the rotary component designs for the water tunnel test fixture. Successful testing in the twelve-inch diameter water tunnel at PSU/ARL demonstrated superior performance with the gap control concept over the protuberance control concept, and efforts are on going to develop the final large scale demonstration. This paper summarizes the results of these activities.