Dynamic shear stress in parallel-plate flow chambers.
An in vitro model using a parallel-plate fluid flow chamber is supposed to simulate in vivo fluid shear stresses on various cell types exposed to dynamic fluid flow in their physiological environment. The metabolic response of cells in vitro is associated with the wall shear stress. However, parallel-plate flow chambers have not been characterized for dynamic fluid flow experiments. We use a dimensionless ratio h / lambda(v), in determining the exact magnitude of the dynamic wall shear stress, with its oscillating components scaled by a shear factor T. It is shown that, in order to expose cells to predictable levels of dynamic fluid shear stress, two conditions have to be met: (1) h / lambda(v) < 2, where h is the distance between the plates and lambda(v) is the viscous penetration depth; and (2) f(0) < f(c) / m, where the critical frequency f(c) is the upper threshold for this flow regime, m is the highest harmonic mode of the flow, and f(0) is the fundamental frequency of fluid flow.
Bacabac
Rommel G
RG
Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam-Vrije Universiteit, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands. rg.bacabac.ocb.acta@med.vu.nl
Smit
Theo H
TH
Cowin
Stephen C
SC
Van Loon
Jack J W A
JJ
Nieuwstadt
Frans T M
FT
Heethaar
Rob
R
Klein-Nulend
Jenneke
J
D000818:Animals; D001826:Body Fluids / Q000502:physiology*; D002468:Cell Physiological Phenomena; D003198:Computer Simulation; D004056:Differential Threshold; D004867:Equipment Design; D006801:Humans; D008954:Models, Biological; D010827:Physiology / Q000295:instrumentation*; D013314:Stress, Mechanical; D014783:Viscosity