Bolus contaminant dispersion for oscillatory flow in a curved tube.
The dispersion of a bolus of soluble contaminant in a curved tube during volume-cycled oscillatory flows is studied. Assuming a small value of delta (the ratio of tube radius to radius of curvature), the Navier-Stokes equations are solved by using a perturbation method. The convection-diffusion equation is then solved by expanding the local concentration in terms of the cross-sectionally averaged concentration and its axial derivatives. The time-averaged dimensionless effective diffusivity, <Deff/D>, is calculated for a range of Womersley number alpha and different values of stroke amplitude A and Schmidt number Sc, where D is the molecular diffusivity of contaminant. For the parameter values considered, the results show that axial dispersion in a curved tube is greater than that in a straight tube, and that it has a local maximum near alpha = 5 for given fixed values of Sc = 1, A = 5 and delta = 0.3. Finally, it is demonstrated how the time history of concentration at a fixed axial position can be used to determine the effective diffusivity.
Jiang
Y
Y
Northwestern University Medical School, Chicago, IL 60611, USA.
Grotberg
J B
JB
D018481:Convection; D004058:Diffusion; D008962:Models, Theoretical; D009991:Oscillometry; D012212:Rheology; D012995:Solubility; D012996:Solutions / Q000493:pharmacokinetics*; D013997:Time Factors; D014783:Viscosity
D012996:Solutions