The Mechanism of Movement and Calculation of Blood Balance in the Flow Channel From the Left Atrium to the End of the Aorta

Author(s):  
E. Talygin ◽  
G. Kiknadze ◽  
A. Gorodkov

Abstract Today, there are a lot of works studying the mechanisms of formation and evolution of self-organizing tornado-like jets of viscous fluid. In these works, the exact solution of the Navier-Stokes equation for such a class of flows are obtained, the geometry of the generating surface for that flows is established and the necessary and sufficient conditions for the formation and evolution of such swirling jets are formulated. However, important aspects of the mechanics of such flows remain unclear — the structure of the boundary layer, the shape of streamlines in general form, the structure of such flows under a pulsating flow regime, and others. After obtaining the exact solution, attempts were made to obtain relations for streamlines in the corresponding projections. However, due to computational complexity, streamlines were constructed only for regions far from the axis of the swirling flow evolution. In this work, an alternative method of calculating streamlines was used, which made it possible to obtain general relations for these lines at each point in space. Expressions for streamlines contain easily computed functions, which simplifies their practical use Based on the expressions for streamlines, expressions were formulated declaring the conservation of the mass of the swirling blood flow from the left atrium to the aorta and the balance of the medium was calculated. The results of this work are of great theoretical and practical importance. On the one hand, the established expressions for streamlines allow a better study of the mechanisms of formation and evolution of swirling flows in the axial region. On the other hand, obtaining quantitative ratios for the balance of blood in the heart and aorta allows a more accurate study of the mechanics of blood circulation.

2005 ◽  
Vol 19 (28n29) ◽  
pp. 1527-1530 ◽  
Author(s):  
R.-K. ZHANG ◽  
Q.-D. CAI ◽  
J.-Z. WU ◽  
Y.-L. WU ◽  
S.-H. LIU ◽  
...  

The physical origin of severe low-frequency pressure fluctuation frequently observed in Francis hydraulic turbines under off-design conditions, which greatly damages the structural stability of turbines and even power stations, is analyzed based on the hydrodynamic stability theory and our Reynolds-averaged Navier-Stokes equation simulation (RANS) of the flow in the entire passage of a Francis turbine. We find that spontaneous unsteady vortex ropes, which induce severe pressure fluctuations, are formed due to the absolute instability of the swirling flow at the conical inlet of the turbine's draft tube.


1986 ◽  
Vol 163 ◽  
pp. 141-147 ◽  
Author(s):  
J. M. Dorrepaal

A similarity solution is found which describes the flow impinging on a flat wall at an arbitrary angle of incidence. The technique is similar to a method used by Jeffery (1915) and discussed more recently by Peregrine (1981).


2017 ◽  
Vol 13 (2) ◽  
pp. 7123-7134 ◽  
Author(s):  
A. S. J Al-Saif ◽  
Takia Ahmed J Al-Griffi

We have proposed in this  research a new scheme to find analytical  approximating solutions for Navier-Stokes equation  of  one  dimension. The  new  methodology depends on combining  Adomian  decomposition  and Homotopy perturbation methods  with the splitting time scheme for differential operators . The new methodology is applied on two problems of  the test: The first has an exact solution  while  the other one has no  exact solution. The numerical results we  obtained  from solutions of two problems, have good convergent  and high  accuracy   in comparison with the two traditional Adomian  decomposition  and Homotopy  perturbationmethods . 


2014 ◽  
Vol 3 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Gunvant A. Birajdar

AbstractIn this paper we find the solution of time fractional discrete Navier-Stokes equation using Adomian decomposition method. Here we discretize the space domain. The graphical representation of solution given by using Matlab software, and it compared with exact solution for alpha = 1.


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