Pressure measurements in highly viscous and elastic fluids

Pressure measurements in flows of highly viscous and elastic fluids are of practical importance in polymer processing and rheology systems. Special pr oblems arise during such pressure measurements. High fluid viscosity result s in excessive dynamic response time (rise time) of the pressure measuring systems. This is true for systems that consist of manometers as well as pre ssure transducers attached to the base of a small hole at the wall. We mode l the dynamic response and examine related disturbing effects. These system atic errors in pressure measurements include hole-pressure effects, instabi lities in cavity flow, and the time lag of the disturbance wave. We conside r static and dynamic flow systems of a polymer solution (PIB/C14/PB Boger f luid) to study these problems and show that instantaneous pressure measurem ents in these systems can effectively be performed. [S0098-2202(00)02703-6] .