My employer has asked me to derive a method or equation for determining noise (in decibels) in orifice flow meters. I was wondering if anyone has any suggestions that could help me get on my way? I've been looking at basic principles of aerodynamic and hydrodynamic noise predicitions. As far as I'm aware there isn't a current standard in place for noise levels in orifice meters but several large companies have generated software packages to calculate noise levels in orifice meters which conform to IEC 534-8-3 and IEC 534-8-4 which details aerodynamic and hydrodynamic noise in throttling valves. My knowledge of Fluid flow is competent/advanced but my knowledge of acoustics is average at best. Anyone with any suggestion? Thanks.