1. The problem statement, all variables and given/known data I understand how to find the resonant frequency of a closed pipe but when the thickness of the walls varies, the resonant frequency varies. Is there a formula that i can use to find the resonant frequency of a closed pipe given the length, temperature, speed of sound and THICKNESS. Thank you for any help :) 2. Relevant equations 3. The attempt at a solution I attempted a few experiments in which i used a technique called over blowing but i also want to calculate it mathematically if possible.