Development of a Periodic Flow in a Rigid Tube

1968 ◽  
Vol 90 (3) ◽  
pp. 395-399 ◽  
Author(s):  
P. J. Florio ◽  
W. K. Mueller

The development of a pulsating velocity field in a rigid, circular tube was experimentally investigated. The wall pressure and the radial variation of the axial velocity were measured at several axial locations. The measured inlet velocities were compared with the fully developed velocities. The experimental results show that, for the range of parameters investigated, the developing pulsating flow can be considered to be simply a superposition of a developing mean flow and a fully developed oscillating flow. These results are in agreement with a previous approximate analytical solution by Atabek and Chang.

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
T. E. Moschandreou ◽  
C. G. Ellis ◽  
D. Goldman

An approximate-analytical solution method is presented for the problem of mass transfer in a rigid tube with pulsatile flow. For the case of constant wall concentration, it is shown that the generalized integral transform (GIT) method can be used to obtain a solution in terms of a perturbation expansion, where the coefficients of each term are given by a system of coupled ordinary differential equations. Truncating the system at some large value of the parameter N, an approximate solution for the system is obtained for the first term in the perturbation expansion, and the GIT-based solution is verified by comparison to a numerical solution. The GIT approximate-analytical solution indicates that for small to moderate nondimensional frequencies for any distance from the inlet of the tube, there is a positive peak in the bulk concentration C1b due to pulsation, thereby, producing a higher mass transfer mixing efficiency in the tube. As we further increase the frequency, the positive peak is followed by a negative peak in the time-averaged bulk concentration and then the bulk concentration C1b oscillates and dampens to zero. Initially, for small frequencies the relative Sherwood number is negative indicating that the effect of pulsation tends to reduce mass transfer. There is a band of frequencies, where the relative Sherwood number is positive indicating that the effect of pulsation tends to increase mass transfer. The positive peak in bulk concentration corresponds to a matching of the phase of the pulsatile velocity and the concentration, respectively, where the unique maximum of both occur for certain time in the cycle. The oscillatory component of concentration is also determined radially in the tube where the concentration develops first near the wall of the tube, and the lobes of the concentration curves increase with increasing distance downstream until the concentration becomes fully developed. The GIT method proves to be a working approach to solve the first two perturbation terms in the governing equations involved.


Author(s):  
Ahmet Yildirim ◽  
Ahmet Gökdogan ◽  
Mehmet Merdan

In this paper, approximate analytical solution of biochemical reaction model is used by the multi-step differential transform method (MsDTM) based on classical differential transformation method (DTM). Numerical results are compared to those obtained by the fourth-order Runge-Kutta method to illustrate the preciseness and effectiveness of the proposed method. Results are given explicit and graphical form.


Author(s):  
José A. Gazquez ◽  
Manuel Fernandez-Ros ◽  
Blas Torrecillas ◽  
José Carmona ◽  
Nuria Novas

1981 ◽  
Vol BME-28 (5) ◽  
pp. 416-420 ◽  
Author(s):  
H. Franken ◽  
J. Cement ◽  
M. Cauberghs ◽  
K. P. Van de Woestijne

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