scholarly journals A Computational Analysis for Active Flow and Pressure Control Using Moving Roller Peristalsis

Computation ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 144
Author(s):  
Iosif Moulinos ◽  
Christos Manopoulos ◽  
Sokrates Tsangaris
Keyword(s):  
Fluid Pressure ◽  
Volumetric Flow Rate ◽  
Pressure Control ◽  
Shear Thinning ◽  
Fluid Volume ◽  
Newtonian Fluids ◽  
Curvilinear Coordinates ◽  
Immersed Boundary ◽  
Strong Positive Correlation ◽  
Volume Rate

Peristaltic motion arises in many physiological, medical, pharmaceutical and industrial processes. Control of the fluid volume rate and pressure is crucial for pumping applications, such as the infusion of intravenous liquid drugs, blood transportation, etc. In this study, a simulation of peristaltic flow is presented in which occlusion is imposed by pairs of circular rollers that squeeze a deformable channel connected to a reservoir with constant fluid pressure. Naturally, this kind of flow is laminar; hence, the computation occurred in this context. The effect of the number and speed of the pairs of rollers, as well as that of the intrapair roller gap, is investigated. Non-Newtonian fluids are considered, and the effect of the shear-thinning behavior degree is examined. The volumetric flow rate is found to increase with an increase in the number of rollers or in the relative occlusion. A reduction in the Bird–Carreau power index resulted in a small reduction in transport efficiency. The characteristic of the pumping was computed, i.e., the induced pressure as a function of the fluid volume rate. A strong positive correlation exists between relative occlusion and induced pressure. Shear-thinning behavior significantly decreases the developed pressure compared to Newtonian fluids. The immersed boundary method on curvilinear coordinates is adapted and validated for non-Newtonian fluids.

scholarly journals Correction to: Stress and pore fluid pressure control of seismicity rate changes following the 2016 Kumamoto earthquake, Japan

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Kodai Nakagomi ◽  
Toshiko Terakawa ◽  
Satoshi Matsumoto ◽  
Shinichiro Horikawa
Keyword(s):  
Fluid Pressure ◽  
Pressure Control ◽  
Pore Fluid ◽  
2016 Kumamoto Earthquake ◽  
Pore Fluid Pressure ◽  
Seismicity Rate ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Seismicity Rate Changes

An amendment to this paper has been published and can be accessed via the original article.

Multiphase Bulk Solids Flow Systems

1980 ◽  
Vol 102 (2) ◽  
pp. 129-132
Author(s):  
R. B. Emery
Keyword(s):  
Soil Mechanics ◽  
Fluid Pressure ◽  
Pressure Control ◽  
Multiphase System ◽  
Mechanical Loads ◽  
Bulk Solids ◽  
Design Goal ◽  
Flow Systems ◽  
Quantitative Design ◽  
Design Construction

Theory and proof are presented here related to fluid pressure control of bulk solids flowability. They are directed toward a quantitative design goal for fluid-solids flow systems. An effort is made to relate multiphase system concept to existing soil mechanics, strength of material and bulk solids flow theory. Gas or liquid interstitial loads often add cumulative effects to the mechanical loads normally considered in bulk solids flow systems. Summation of the mechanical, gas and liquid loads form the basis for multiphase system design. Useful savings in design, construction and maintenance are expected from application of multiphase theory. Quantitative design can, in some cases, provide flow, no-flow, or a controlled combination of flow and no-flow.

Formation of droplet of shear‐thinning non‐Newtonian fluids in a step‐emulsification microdevice

AIChE Journal ◽  
2021 ◽  
Author(s):  
Xiyang Liu ◽  
Ziwei Liu ◽  
Shaokun Jiang ◽  
Chunying Zhu ◽  
Youguang Ma ◽  
...  
Keyword(s):  
Shear Thinning ◽  
Newtonian Fluids

Sedimentation of finite-size particles in quiescent wall-bounded shear-thinning and Newtonian fluids

2020 ◽  
Vol 129 ◽  
pp. 103291
Author(s):  
Dhiya Alghalibi ◽  
Walter Fornari ◽  
Marco E. Rosti ◽  
Luca Brandt
Keyword(s):  
Finite Size ◽  
Shear Thinning ◽  
Newtonian Fluids

Relationship between interstitial fluid volume and pressure (compliance) in hypothyroid rats

2001 ◽  
Vol 281 (3) ◽  
pp. H1085-H1092 ◽  
Author(s):  
Helge Wiig ◽  
Tjøstolv Lund
Keyword(s):  
Skeletal Muscle ◽  
Peritoneal Dialysis ◽  
Thyroid Hormones ◽  
Interstitial Fluid ◽  
Experimental Situation ◽  
Fluid Pressure ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
The Body ◽  
Interstitial Fluid Volume

There is clinical and experimental evidence that lack of thyroid hormones may affect the composition and structure of the interstitium. This can influence the relationship between volume and pressure during changes in hydration. Hypothyrosis was induced in rats by thyroidectomy 8 wk before the experiments. Overhydration was induced by infusion of acetated Ringer, 5, 10, and 20% of the body weight, while fluid was withdrawn by peritoneal dialysis with hypertonic glucose. Interstitial fluid pressure (Pi) in euvolemia (euvolemic control situation) and experimental situation was measured with micropipettes connected to a servocontrolled counterpressure system. The corresponding interstitial fluid volume (Vi) was found as the difference between extracellular fluid volume measured as the distribution volume of 51Cr-labeled EDTA and plasma volume measured using125I-labeled human serum albumin. In euvolemia, Vi was similar or lower in the skin and higher in skeletal muscle of hypothyroid than in euthyroid control rats, whereas the corresponding Pi was higher in all tissues. During overhydration, Pi rose to the same absolute level in both types of rats, whereas during peritoneal dialysis there was a linear relationship between volume and pressure in all tissues and types of rats. Interstitial compliance (Ci), calculated as the inverse value of the slope of the curve relating changes in volume and pressure in dehydration, did not differ significantly in the hindlimb skin of hypothyroid and euthyroid rats. However, in skeletal muscle, Ci was 1.3 and 2.0 ml · 100 g−1 · mmHg−1 in hypothyroid and euthyroid rats ( P < 0.01), with corresponding numbers for the back skin of 2.7 and 5.0 ml · 100 g−1 · mmHg−1 ( P < 0.01). These experiments suggest that lack of thyroid hormones in rats changes the interstitial matrix, again leading to reduced Ci and reduced ability to mobilize fluid from the interstitium.

Droplet Formation and Fission in Shear-Thinning/Newtonian Multiphase System Using Bilayer Bifurcating Microchannel

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Yong Ren ◽  
Kai Seng Koh ◽  
Jit Kai Chin ◽  
Jing Wang ◽  
Conghua Wen ◽  
...  
Keyword(s):  
Shear Thinning ◽  
Droplet Formation ◽  
Newtonian Fluids ◽  
Model Systems ◽  
Multiphase System ◽  
Blood Capillaries ◽  
Two Systems ◽  
Flow Through ◽  
Newtonian System ◽  
Droplet Fission

With a novel platform of bilayer polydimethylsiloxane microchannel formed by bifurcating junction, we aim to investigate droplet formation and fission in a multiphase system with complex three-dimensional (3D) structure and understand the variations in mechanism associated with droplet formation and fission in the microstructure between shear-thinning/Newtonian system versus Newtonian/Newtonian system. The investigation concentrates on shear-thinning fluid because it is one of the most ubiquitous rheological properties of non-Newtonian fluids. Sodium carboxymethyl cellulose (CMC) solution and silicone oil have been used as model fluids and numerical model has been established to characterize the shear-thinning effect in formation of CMC-in-oil emulsions, as well as breakup dynamics when droplets flow through 3D bifurcating junction. The droplet volume and generation rate have been compared between two systems at the same Weber number and capillary number. Variation in droplet fission has been found between two systems, demonstrating that the shear-thinning property and confining geometric boundaries significantly affect the deformation and breakup of each mother droplet into two daughter droplets at bifurcating junction. The understanding of the droplet fission in the novel microstructure will enable more versatile control over the emulsion formation and fission when non-Newtonian fluids are involved. The model systems in the study can be further developed to investigate the mechanical property of emulsion templated particles such as drug encapsulated microcapsules when they flow through complex media structures, such as blood capillaries or the porous tissue structure, which feature with bifurcating junction.

scholarly journals Edemagenic gain and interstitial fluid volume regulation

2008 ◽  
Vol 294 (2) ◽  
pp. R651-R659 ◽  
Author(s):  
R. M. Dongaonkar ◽  
C. M. Quick ◽  
R. H. Stewart ◽  
R. E. Drake ◽  
C. S. Cox ◽  
...  
Keyword(s):  
Fluid Balance ◽  
Interstitial Fluid ◽  
Fluid Pressure ◽  
Venous Hypertension ◽  
Fluid Volume ◽  
Balance Equations ◽  
Factors Affecting ◽  
Venous Circulation ◽  
Interstitial Fluid Volume ◽  
Simplifying Assumptions

Under physiological conditions, interstitial fluid volume is tightly regulated by balancing microvascular filtration and lymphatic return to the central venous circulation. Even though microvascular filtration and lymphatic return are governed by conservation of mass, their interaction can result in exceedingly complex behavior. Without making simplifying assumptions, investigators must solve the fluid balance equations numerically, which limits the generality of the results. We thus made critical simplifying assumptions to develop a simple solution to the standard fluid balance equations that is expressed as an algebraic formula. Using a classical approach to describe systems with negative feedback, we formulated our solution as a “gain” relating the change in interstitial fluid volume to a change in effective microvascular driving pressure. The resulting “edemagenic gain” is a function of microvascular filtration coefficient ( K f), effective lymphatic resistance ( R L), and interstitial compliance ( C). This formulation suggests two types of gain: “multivariate” dependent on C, R L, and K f, and “compliance-dominated” approximately equal to C. The latter forms a basis of a novel method to estimate C without measuring interstitial fluid pressure. Data from ovine experiments illustrate how edemagenic gain is altered with pulmonary edema induced by venous hypertension, histamine, and endotoxin. Reformulation of the classical equations governing fluid balance in terms of edemagenic gain thus yields new insight into the factors affecting an organ's susceptibility to edema.

Modelling of Laminar Canonical Flows: Revisit

2012 ◽  
Author(s):  
Kofi Freeman K. Adane ◽  
Mark F. Tachie
Keyword(s):  
Three Dimensional ◽  
Shear Thinning ◽  
Secondary Flows ◽  
Newtonian Fluids ◽  
Navier Stokes ◽  
Jet Flows ◽  
Wall Jet ◽  
Navier Stokes Equation ◽  
Incompressible Navier Stokes Equation ◽  
Insight Into

Three-dimensional laminar lid-driven and wall jet flows of various shear-thinning non-Newtonian and Newtonian fluids were numerically investigated. The complete nonlinear incompressible Navier-Stokes equation was solved using a collocated finite-volume based in-house CFD code. From the results, velocity profiles at several locations, jet spread rates, secondary flows and vorticity distributions were used to provide insight into the characteristics of three-dimensional laminar canonical flows of shear-thinning non-Newtonian and Newtonian fluids.

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