Effective Beam Angle : That beam angle which, when plotted for a flat workpiece of the same thickness, accounts for the lengthening of skip distance which occurs in a curved test piece. (RP 2X)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}