Ultrasound sensor design

We need a design with a piezo electric transducer which will be transmitter and receiver of the ultrasound signal. We use an angle of incidence of 45°, and we are looking for less than 10% in the percentage of error in velocity measurement of the flow. We will give more details about the transmiter signal used and the resonance frequency if you are selected. The output files for this project are: 1) Design and improve of the design concept developed. 2) Bill of materials (with Manufacture part numbers, Material used for design should have quality documentation) 3) CAD files and diagrams 4) Simulations and calculations used to define the design So looking for someone with expertise in Mechanical as well in Cosmol