Abstract
In this paper, we report a method to control acoustic field in a main pipe of a thermoacoustic engine by onnecting a branch duct. This method is based on the fact that the complex acoustic admittance in the main pipe discontinuously changes at the position where the branch duct is connected. It is demonstrated that the connection of the branch duct with a proper length at a right position turns the existing acoustic field in the main pipe to a pure traveling wave field without introducing the acoustic power loss flowing down the branch duct. This method would be applicable to various thermoacoustic devices such as a looped-tube traveling wave engine.
