The effect of a bump in an elastic tube on wave propagation in a viscous fluid of variable viscosity
In the present work treating the arteries as a thin walled prestressed elastic tube with a bump and the blood as a Newtonian fluid of variable viscosity we have studied the propagation of weakly nonlinear waves in such a medium by employing the reductive perturbation method in the longwave approximation. Korteweg-deVries-Burgers equation with variable coefficients is obtained as the evolution equation. Seeking a progressive wave type of solution to this evolution equation it is observed that the wave speed is variable. The numerical calculations show that the wave speed reaches to its maximum value at the center of the bump but it gets smaller and smaller as we go away from the center of the bump. Such a result seems to be reasonable from physical considerations. © 2006 Elsevier Inc. All rights reserved.