M. Whittle et al., ELECTRORHEOLOGICAL RELAXATION-TIMES DERIVED FROM PRESSURE RESPONSE EXPERIMENTS IN THE FLOW MODE, Journal of non-Newtonian fluid mechanics, 57(1), 1995, pp. 1-25
We examine the experimental pressure response for a set of electrorheo
logical valves operating at several steady flow rates to step function
voltage inputs and analyse the factors that may contribute to the com
plex forms observed. Using a numerical algorithm incorporating a visco
elastic model for the fluid the response of the valve flow profile to
changes in theology is found to be relatively fast compared to the exp
erimental pressure response and thought not to feature as a significan
t contribution to the final shape. The dynamic interaction of the valv
e and its associated system of pump and connecting pipes is investigat
ed using a multi-element lumped parameter model and reveals a frequenc
y spectrum containing resonances comparable to the experimental result
s. A simple lumped parameter model is less successful. Using the multi
-element model for the system an upper bound can be placed on the basi
c response time of the electro-stress itself under realistic engineeri
ng conditions.