Framework to characterize nonlinear flow through pervious concrete

2022 ◽  
Vol 151 ◽  
pp. 106633
Author(s):  
Sergio Tunis Martins Filho ◽  
Ricardo Pieralisi ◽  
Fábio Cunha Lofrano
Keyword(s):  
Pervious Concrete ◽  
Nonlinear Flow ◽  
Flow Through

scholarly journals Experimental Study on Strength of Pervious Concrete by Using Fine Aggregate

2021 ◽  
Vol 9 (12) ◽  
pp. 895-897
Author(s):  
Atif Jawed
Keyword(s):  
Compressive Strength ◽  
Void Ratio ◽  
Rice Husk Ash ◽  
Pervious Concrete ◽  
Void Content ◽  
Fine Aggregate ◽  
Coarse Aggregates ◽  
Fine Aggregates ◽  
Flow Through ◽  
Concrete Matrix

Abstract: Pervious concrete is a special type of concrete, which consists of cement, coarse aggregates, water and if required and other cementations materials. As there are no fine aggregates used in the concrete matrix, the void content is more which allows the water to flow through its bodyThe main aim of this project was to improve the compressive strength characteristics of pervious concrete. But it can be noted that with increase in compressive strength the void ratio decreases. Hence, the improvement of strength should not affect the porosity property because it is the property which serves its purpose. In this investigation work the compressive strength of pervious concrete is increased by a maximum of 18.26% for 28 days when 8% fine aggregates were added to standard pervious concrete Keywords: W/C ratio, pervious Concrete, sugarcane bagasse’s ash, rice husk ash compressive strength, fine aggregates

Darcy’s Experiments and the Deviation to Nonlinear Flow Regime

2000 ◽  
Vol 122 (3) ◽  
pp. 619-625 ◽  
Author(s):  
J. L. Lage ◽  
B. V. Antohe
Keyword(s):  
Flow Regime ◽  
Additional Data ◽  
Quadratic Extension ◽  
Nonlinear Flow ◽  
Data Set ◽  
Natural Processes ◽  
Darcy Equation ◽  
Flow Through ◽  
Cubic Extension ◽  
Consistent Parameter

Many important technological and natural processes involving flow through porous media are characterized by large filtration velocity. It is important to know when the transition from the linear flow regime to the quadratic flow regime actually occurs to obtain accurate models for these processes. By interpreting the quadratic extension of the original Darcy equation as a model of the macroscopic form drag, we suggest a physically consistent parameter to characterize the transition to quadratic flow regime in place of the Reynolds number, Re. We demonstrate that an additional data set obtained by Darcy, and so far ignored by the community, indeed supports the Darcy equation. Finally, we emphasize that the cubic extension proposed in the literature, proportional to Re3 and mathematically valid only for Re≪1, is irrelevant in practice. Hence, it should not be compared to the quadratic extension experimentally observed when Re⩾O1.[S0098-2202(00)01703-X]

Nonlinear Flow Through an Anisotropic Porous Media

1995 ◽  
Vol 38 (3) ◽  
pp. 863-868
Author(s):  
A. T. Hjelmfelt Jr. ◽  
D. B. Brooker
Keyword(s):  
Porous Media ◽  
Nonlinear Flow ◽  
Anisotropic Porous Media ◽  
Flow Through

Direct Simulation Based Model-Predictive Control of Flow Maldistribution in Parallel Microchannels

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
Mathieu Martin ◽  
Chris Patton ◽  
John Schmitt ◽  
Sourabh V. Apte
Keyword(s):  
Fluid Flow ◽  
Model Predictive Control ◽  
Numerical Simulations ◽  
Active Control ◽  
Predictive Control ◽  
Nonlinear Flow ◽  
Flow Simulations ◽  
Flow Through ◽  
Parallel Microchannels ◽  
Flow Maldistribution

Flow maldistribution, resulting from bubbles or other particulate matter, can lead to drastic performance degradation in devices that employ parallel microchannels for heat transfer. In this work, direct numerical simulations of fluid flow through a prescribed parallel microchannel geometry are performed and coupled with active control of actuated microvalves to effectively identify and reduce flow maldistribution. Accurate simulation of fluid flow through a set of three parallel microchannels is achieved utilizing a fictitious-domain representation of immersed objects such as microvalves and artificially introduced bubbles. Flow simulations are validated against experimental results obtained for flow through a single high-aspect ratio microchannel, flow around an oscillating cylinder, and flow with a bubble rising in an inclined channel. Results of these simulations compare very well to those obtained experimentally, and validate the use of the solver for the parallel microchannel configuration of this study. System identification techniques are employed on numerical simulations of fluid flow through the geometry to produce a lower dimensional model that captures the essential dynamics of the full nonlinear flow, in terms of a relationship between valve angles and the exit flow rate for each channel. A model-predictive controller is developed, which employs this reduced order model to identify flow maldistribution from exit flow velocities and to prescribe actuation of channel valves to effectively redistribute the flow. Flow simulations with active control are subsequently conducted with artificially introduced bubbles. The model-predictive control methodology is shown to adequately reduce flow maldistribution by quickly varying channel valves to remove bubbles and to equalize flow rates in each channel.

scholarly journals Experimental Study on Stress-Dependent Nonlinear Flow Behavior and Normalized Transmissivity of Real Rock Fracture Networks

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Qian Yin ◽  
Hongwen Jing ◽  
Richeng Liu ◽  
Guowei Ma ◽  
Liyuan Yu ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Rock Fracture ◽  
Hydraulic Gradient ◽  
Nonlinear Flow ◽  
Fracture Networks ◽  
Critical Hydraulic Gradient ◽  
Boundary Load ◽  
Flow Through ◽  
Stress Dependent ◽  
Rock Fracture Networks

The mechanism and quantitative descriptions of nonlinear fluid flow through rock fractures are difficult issues of high concern in underground engineering fields. In order to study the effects of fracture geometry and loading conditions on nonlinear flow properties and normalized transmissivity through fracture networks, stress-dependent fluid flow tests were conducted on real rock fracture networks with different number of intersections (1, 4, 7, and 12) and subjected to various applied boundary loads (7, 14, 21, 28, and 35 kN). For all cases, the inlet hydraulic pressures ranged from 0 to 0.6 MPa. The test results show that Forchheimer’s law provides an excellent description of the nonlinear fluid flow in fracture networks. The linear coefficient a and nonlinear coefficient b in Forchheimer’s law J=aQ+bQ2 generally decrease with the number of intersections but increase with the boundary load. The relationships between a and b can be well fitted with a power function. A nonlinear effect factor E=bQ2/(aQ+bQ2) was used to quantitatively characterize the nonlinear behaviors of fluid flow through fracture networks. By defining a critical value of E = 10%, the critical hydraulic gradient was calculated. The critical hydraulic gradient decreases with the number of intersections due to richer flowing paths but increases with the boundary load due to fracture closure. The transmissivity of fracture networks decreases with the hydraulic gradient, and the variation process can be estimated using an exponential function. A mathematical expression T/T0=1-exp⁡(-αJ-0.45) for decreased normalized transmissivity T/T0 against the hydraulic gradient J was established. When the hydraulic gradient is small, T/T0 holds a constant value of 1.0. With increasing hydraulic gradient, the reduction rate of T/T0 first increases and then decreases. The equivalent permeability of fracture networks decreases with the applied boundary load, and permeability changes at low load levels are more sensitive.

scholarly journals Critical behaviour of the MHD flow in convergent-divergent channels

2011 ◽  
Vol 7 (2) ◽  
pp. 83-93 ◽  
Author(s):  
Md. Sarwar Alam ◽  
Md. Abdul Hakim Khan
Keyword(s):  
Power Series ◽  
Mhd Flow ◽  
Conducting Fluid ◽  
Critical Behaviour ◽  
Nonlinear Flow ◽  
Two Dimensional ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
Flow Through ◽  
Principal Singularity

The effect of external Magnetohydrodynamic (MHD) field on the steady two-dimensional nonlinear flow through Convergent-Divergent Channels of a viscous incompressible electrically conducting fluid is investigated. We compute the critical behaviour of the solution govern by the equation. Our approach uses the power series in order to observe the instability of the problem. The series is then summed by using various generalizations of the approximants. We find the critical values of various parameters and type of the principal singularity for different choice of MHD effect.DOI: 10.3329/jname.v7i2.5635

Electro-Osmotic Flow With Free Surface in Nanochannels

2008 ◽  
Author(s):  
Sang W. Joo ◽  
Shizhi Qian ◽  
Yingtao Jiang ◽  
Marcos A. Cheney
Keyword(s):  
Free Surface ◽  
Flow Behavior ◽  
Film Surface ◽  
Interfacial Instability ◽  
Nonlinear Flow ◽  
Thin Film Flow ◽  
Electro Osmosis ◽  
New Type ◽  
Flow Through ◽  
Nonlinear Flow Behavior

A thin-film flow induced by the electro-osmosis is studied. In contrast to the single-phase electro-osmosis flow through micro- and nanochannels, the flow considered has a free surface, which may deform with the flow developments. A new type of interfacial instability is identified via a linear stability analysis, and subsequent nonlinear flow behavior, including that for the film surface corrugations, is examined by deriving an evolution equation.

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