Abstract: Apparatus and method for determining the frequency response of an acoustic ensor of a line array embedded in an elastic material to a momentary force applied to the elastic material at any point thereof. The apparatus includes a longitudinal box which has its bottom and two opposite side ends open. The device includes a slider movable at the top of the box which has an attached pivoted arm at the top. The pivoted arm has a force gauge secured thereto. The box is placed over the line array under test and the arm is pivoted to strike the surface of the line array. The force gauge attached to the pivoted arm measures the applied force while the electrical signals generated by the line array are used to find the frequency response of the acoustic sensor of the line array.

Abstract: A turbulent flow apparatus for laboratory use that provides a turbulent f field around the circumference of a cylindrical line array. The apparatus enables an evaluation of the response characteristics of the acoustic sensors in the line array to the resultant pressure field similar to the one present when the line array is towed at sea or is subject to flow. The apparatus includes a small cylindrical chamber which can be assembled around the portion of a line array under test. Water from a source is supplied at one end of the chamber through inlets and a turbulent flow is attained by the water as it comes out of the opposite end of the chamber. The portion of the array containing the hydrophones under test are placed in the water to simulate the flow environment encountered at sea.