About some application of special purpose Trefftz function for determination of effective viscosity in filtration equation

2016 ◽  
Author(s):  
Jan Adam Kolodziej ◽  
Magdalena Mierzwiczak ◽  
Jakub Krzysztof Grabski
Keyword(s):  
Effective Viscosity ◽  
Filtration Equation

Determination of an Effective Viscosity of Powders as a Function of Temperature

1970 ◽  
pp. 185-202 ◽  
Author(s):  
Wayne S. Young ◽  
Stephen T. Rasmussen ◽  
Ivan B. Cutler
Keyword(s):  
Effective Viscosity

scholarly journals Effective viscosity of puller-like microswimmers: a renormalization approach

2013 ◽  
Vol 10 (89) ◽  
pp. 20130720 ◽  
Author(s):  
Simon Gluzman ◽  
Dmitry A. Karpeev ◽  
Leonid V. Berlyand
Keyword(s):  
Renormalization Group ◽  
Critical Point ◽  
Effective Viscosity ◽  
Collective Motion ◽  
Analytical Determination ◽  
Renormalization Approach ◽  
Theoretical Results ◽  
Better Than ◽  
Passive Suspensions

Effective viscosity (EV) of suspensions of puller-like microswimmers (pullers), for example Chlamydamonas algae, is difficult to measure or simulate for all swimmer concentrations. Although there are good reasons to expect that the EV of pullers is similar to that of passive suspensions, analytical determination of the passive EV for all concentrations remains unsatisfactory. At the same time, the EV of bacterial suspensions is closely linked to collective motion in these systems and is biologically significant. We develop an approach for determining analytical EV estimates at all concentrations for suspensions of pullers as well as for passive suspensions. The proposed methods are based on the ideas of renormalization group (RG) theory and construct the EV formula based on the known asymptotics for small concentrations and near the critical point (i.e. approaching dense packing). For passive suspensions, the method is verified by comparison against known theoretical results. We find that the method performs much better than an earlier RG-based technique. For pullers, the validation is done by comparing them to experiments conducted on Chlamydamonas suspensions.

A determination of the effective viscosity for the Brinkman–Forchheimer flow model

1994 ◽  
Vol 258 ◽  
pp. 355-370 ◽  
Author(s):  
R. C. Givler ◽  
S. A. Altobelli
Keyword(s):  
Effective Viscosity ◽  
Average Velocity ◽  
Flow Model ◽  
High Porosity ◽  
Rigid Foam ◽  
Nmr Techniques ◽  
Flow Through ◽  
Forchheimer Flow ◽  
Average Velocity Profile

The effective viscosity μe for the Brinkman–Forchheimer flow (BFF) model has been determined experimentally for steady flow through a wall-bounded porous medium. Nuclear magnetic resonance (NMR) techniques were used to measure non-invasively the ensemble-average velocity profile of water flowing through a tube filled with an open-cell rigid foam of high porosity (ϕ = 0.972). By comparing these data with the BFF model, for which all remaining parameters were measured independently, it was determined that μe = (7.5+3.4−2.4)μf, where μf was the viscosity of the fluid. The Reynolds number, based upon the square root of the permeability, was 17.

FLOW MODIFICATION INDUCED BY QUINCKE ROTATION IN A CAPILLARY

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2603-2609 ◽  
Author(s):  
A. CEBERS ◽  
E. LEMAIRE ◽  
L. LOBRY
Keyword(s):  
Cross Section ◽  
Flow Rate ◽  
Effective Viscosity ◽  
Rectangular Cross Section ◽  
Colloidal Suspension ◽  
Direct Determination ◽  
Flow Modification ◽  
Insulating Liquid ◽  
Quincke Rotation

When particles immersed in a semi-insulating liquid are submitted to a sufficiently high DC field, they can rotate spontaneously around any axis perpendicular to the field (Quincke rotation). Recently we have shown that due to Quincke effect the effective viscosity of a colloidal suspension could be reduced. When the suspension is submitted to a shear, the particles rotation is amplified by the electric torque and drives the suspending liquid. For a flow in a capillary, this effect manifests itself by an increase of the flow rate. We present the results of our experiments carried out with a rectangular cross section capillary. These results are compared with the direct determination of the apparent viscosity in a Couette flow rheometer.

scholarly journals Model of layered flow of viscous-plastic Bingham fluid in the extruder channel

2018 ◽  
Vol 80 (2) ◽  
pp. 58-63
Author(s):  
A. V. Gukasyan
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Plastic Flow ◽  
Significant Influence ◽  
Effective Viscosity ◽  
Piston Flow ◽  
Layered Flow ◽  
Discharge Pressure ◽  
Pressure Characteristics

The analysis is carried out and the presence of a zone of a piston flow, which has a significant influence both on the process of extrusion, and on the determination of the discharge-pressure characteristics of the screw, is established. It is noted that the effective viscosity has a physical meaning if the shear rate to which it corresponds is indicated. The effective viscosity is considered to consist of two components: the plastic viscosity corresponding to the viscosity of the Newtonian fluid and the structural viscosity that characterizes the shear resistance caused by the tendency of the solid particles contained in the Bingham liquid to form a structure. The effective viscosity is introduced into many hydrodynamic equations if the shear rate to which it corresponds is known. In the auger channel there are zones of forced flow created by the dynamic shear stress and the reverse flow of the head resistance created by the overpressure. The shear rate in the auger channel is marked by considerable heterogeneity and determines the complex nature of the shear deformation of the material during extrusion. Regardless of the pressure amplitude, the rigid core can not completely disappear, because for very small dimensions of the nucleus the pressure value must be very large, and with the disappearance of the plastic flow it must become infinite. Thus, the dependence of the shear stress on the shear rate for the flow of a Bingham viscoplastic fluid is always nonlinear for any values of the shear rate. An important element in the calculation of the discharge-pressure characteristics of the extrusion process is the localization of the plastic flow in the screw channel. As a result of the analysis of the model of the layered flow of viscoplastic Bingham liquid in the extruder channel, it is established that there is a zone of piston flow that exerts a significant influence both on the process of extrusion and on the determination of the discharge and pressure characteristics of the screw.

scholarly journals Flow Velocity and Effective Viscosity of a Fluid Containing Rigid Cylindrical Inclusions

2005 ◽  
Vol 60 (6) ◽  
pp. 401-407 ◽  
Author(s):  
Siegfried Hess
Keyword(s):  
Effective Viscosity ◽  
Volume Fraction ◽  
Dimensional Problem ◽  
Flow Properties ◽  
Cylindrical Inclusions ◽  
Dilute Suspension ◽  
Oriented Parallel ◽  
Relative Change ◽  
Special Case

The determination of the flow properties of a fluid containing a cylindrical inclusion with its long axis oriented parallel to the vorticity direction is a 2-dimensional problem which is treated as a special case in a calculation of the corresponding D-dimensional problem. The velocity and pressure are obtained from the solution of the equations of hydrodynamics where D-dimensional multipole potential tensors are used. The effective viscosity of a dilute suspension is evaluted via the entropy production, as suggested by Einstein, and via an effective stress tensor. The relative change of the viscosity is proportional to the volume fraction. For D = 2 the proportionality factor Z is found to be 2 and 3 when the inclusion rotates with an angular velocity equal to the vorticity and when the inclusion does not rotate, repectively. The corresponding results for D=3 are the well known number Z = 2.5 and Z = 4.

scholarly journals JUSTIFICATION OF USING A SCREEN MODEL TO PREDICT THE EFFECTIVE VISCOSITY OF PPG IN OPEN FRACTURES

2016 ◽  
pp. 84-86
Author(s):  
S. K. Sokhoshko ◽  
G. H. Ali
Keyword(s):  
Pressure Gradient ◽  
Effective Viscosity ◽  
Viscoelastic Liquid ◽  
Oil Fields ◽  
Fracture Model ◽  
Injection Velocity ◽  
Fracture Width ◽  
Gel Injection ◽  
Screen Model

This work purpose was to develop a method for determination of the effective viscosity of the granulated gel PPG for blocking anthropogenic fractures (auto-FHF fractures) which is applied at later stages of oil fields development. Using the laboratory fracture model the values of constants (apparent constant consistency and the apparent index of pseudoplasticity) for the equation of viscoelastic liquid were obtained. The same constants were used to derive the equation for pressure gradient along the anthropogenic fracture. The gel viscosity is calculated by the equation of gel movement along the fracture. This equation enables to predict the gel viscosity for each size of granulated gel fractions depending on the fracture width and the gel injection velocity.

Sign in / Sign up

Export Citation Format

Share Document