Maxwell fluid flow in system supplying hydrodynamically active polymer to boundary layer of streamlined object

2020 ◽  
Vol 8 (1) ◽  
pp. 58-68
Author(s):  
V. G. Pogrebnyak ◽  
◽  
A. V. Pogrebnyak ◽  
I. V. Perkun ◽  
◽  
...  

The article presents the results of the numerical simulation of the Maxwell fluid flow in the system supplying hydrodynamically active polymer in the boundary layer of a streamlined object. The case of slow flow is considered. In this case, the inertial terms can be neglected, the velocities, stresses, and stream functions can be written as the decomposition by Weisenberg number, and we can assume that the Weissenberg number is less than one. The established features of the behaviour of the Maxwell fluid flow with a longitudinal velocity gradient and the manifestation of the effects of elastic deformations are crucial for understanding processes taking place in the system supplying hydrodynamically active polymer in the boundary layer of a streamlined object. Understanding the nature of the effects of elastic deformations in the supplying system makes it possible to offer a hydrodynamic calculation of the modes of polymer solution injection into the boundary layer without any negative manifestations of the effects of the elastic deformations. The results of the numerical simulation confirmed the conception on the deformation-stress state of macromolecules (fluid elements) in polymer solution converging flow, based on the data previously obtained from experimental decisions concerning the hydrodynamic field structure in the input area of a slot and other openings.

Author(s):  
N. Ashrafi ◽  
M. Mohamadali ◽  
M. Najafi

The classic Blassius problem of steady boundary-layer flow of the upper convected Maxwell over a flat plate in a moving fluid is studied. According to scaling parameters the equations represent the viscoelastic stress boundary layer. By means of an exact similarity transformation, the non-linear viscoelastic momentum and constitutive equations transform into a system of highly nonlinear coupled ordinary differential equations. Numerical solution may be achieved by a variable stepping method for the initial-value problem. The stepping numerical method chosen fifth order Runge-Kutta for solving the resulting nonlinear algebraic equations at each step. It is seen that there is a stress boundary layer and there is no velocity boundary layer.


2021 ◽  
Vol 2057 (1) ◽  
pp. 012006
Author(s):  
A I Kadyirov ◽  
R R Zaripov ◽  
E R Kutuzova ◽  
E K Vachagina

Abstract A numerical simulation of a viscoelastic fluid flow past a sphere in a round pipe is carried out. The four mode Giesekus model is taken as a rheological model. By the example of a polymer melt flow, the features of the flow around a sphere in comparison with the flow around a cylinder are revealed. Velocity and stress profiles for polymer melt and polymer solution fluid flow around a sphere at the same Weissenberg numbers are analyzed.


2020 ◽  
Vol 65 (1) ◽  
pp. 51-58
Author(s):  
Sava Ianici

The paper presents the results of research on the study of the elastic deformation of a flexible wheel from a double harmonic transmission, under the action of a cam wave generator. Knowing exactly how the flexible wheel is deformed is important in correctly establishing the geometric parameters of the wheels teeth, allowing a better understanding and appreciation of the specific conditions of harmonic gearings in the two stages of the transmission. The veracity of the results of this theoretical study on the calculation of elastic deformations and displacements of points located on the average fiber of the flexible wheel was subsequently verified and confirmed by numerical simulation of the flexible wheel, in the elastic field, using the finite element method from SolidWorks Simulation.


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