INFLUENCE OF PERISTALTIC CONTRACTION OF DISTAL COLON ON BLOOD FLOW THROUGH COLONIC VEIN

As it is known, the Womersley function models velocity as a function of radius and time. It has been widely used to simulate the pulsatile blood flow through circular ducts. In this context, the present study is focused on the introduction of a simple function as an approximation of the Womersley function in order to evaluate its accuracy. This approximation consists of a simple quadratic function, suitable to be implemented in most commercial and non-commercial computational fluid dynamics codes, without the aid of external mathematical libraries. The Womersley function and the new function have been implemented here as boundary conditions in OpenFOAM ESI software (v.1906). The discrepancy between the obtained results proved to be within 0.7%, which fully validates the calculation approach implemented here. This approach is valid when a simplified analysis of the system is pointed out, in which flow reversals are not contemplated.

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Mechanics of non-Newtonian blood flow in an artery having multiple stenosis and electroosmotic effects

Science Progress ◽

10.1177/00368504211031693 ◽

2021 ◽

Vol 104 (3) ◽

pp. 003685042110316

Author(s):

Salman Akhtar ◽

Luthais B McCash ◽

Sohail Nadeem ◽

Salman Saleem ◽

Alibek Issakhov

Keyword(s):

Blood Flow ◽

Flow Problem ◽

Fluid Model ◽

Casson Fluid ◽

Viscous Effects ◽

Heating Effects ◽

Casson Fluid Model ◽

Flow Through ◽

Mathematical Equations ◽

Mathematica Software

The electro-osmotically modulated hemodynamic across an artery with multiple stenosis is mathematically evaluated. The non-Newtonian behaviour of blood flow is tackled by utilizing Casson fluid model for this flow problem. The blood flow is confined in such arteries due to the presence of stenosis and this theoretical analysis provides the electro-osmotic effects for blood flow through such arteries. The mathematical equations that govern this flow problem are converted into their dimensionless form by using appropriate transformations and then exact mathematical computations are performed by utilizing Mathematica software. The range of the considered parameters is given as [Formula: see text]. The graphical results involve combine study of symmetric and non-symmetric structure for multiple stenosis. Joule heating effects are also incorporated in energy equation together with viscous effects. Streamlines are plotted for electro-kinetic parameter [Formula: see text] and flow rate [Formula: see text]. The trapping declines in size with incrementing [Formula: see text], for symmetric shape of stenosis. But the size of trapping increases for the non-symmetric case.

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Krypton 85 myocardial blood flow: precordial scintillation versus coronary sinus sampling

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1965.209.4.705 ◽

1965 ◽

Vol 209 (4) ◽

pp. 705-710 ◽

Cited By ~ 34

Author(s):

Michael D. Klein ◽

Lawrence S. Cohen ◽

Richard Gorlin

Keyword(s):

Blood Flow ◽

Myocardial Blood Flow ◽

Coronary Sinus ◽

Human Subjects ◽

Radioactive Decay ◽

Empirical Correction ◽

Wide Range ◽

Actual Flow ◽

Flow Through ◽

High Degree

Myocardial blood flow in human subjects was assessed by comparative simultaneous measurement of krypton 85 radioactive decay from coronary sinus and precordial scintillation. Empirical correction of postclearance background from precordial curves yielded a high degree of correlation between flows derived from the two sampling sites (r = .889, P < .001). Comparison of left and right coronary flows in nine subjects revealed similarity in flow through the two vessels over a wide range of actual flow values (r = .945, P < .001).

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