An apparatus and method are disclosed wherein at least one parameter associated with a core-annular flow (CAF) in a pipe is measured by sensing unsteady pressures associated with undulations formed at the interface of a core region and an annular region in the CAF at different axial locations along the...http://www.google.com/patents/US7150202?utm_source=gb-gplus-sharePatent US7150202 - Method and apparatus for measuring characteristics of core-annular flow
