scholarly journals Combining spectral and POD modes to improve error estimation of numerical model reduction for porous media

2021 ◽  
Author(s):  
Fredrik Ekre ◽  
Fredrik Larsson ◽  
Kenneth Runesson ◽  
Ralf Jänicke
Keyword(s):  
Porous Media ◽  
Numerical Model ◽  
Model Reduction ◽  
Error Control ◽  
Mode Selection ◽  
Selection Strategy ◽  
Error Estimator ◽  
Reduced Basis ◽  
The One ◽  
Estimated Error

AbstractNumerical model reduction (NMR) is used to solve the microscale problem that arises from computational homogenization of a model problem of porous media with displacement and pressure as unknown fields. The reduction technique and an associated error estimator for the NMR error have been presented in prior work, where both spectral decomposition (SD) and proper orthogonal decomposition (POD) were used to construct the reduced basis. It was shown that the POD basis performs better w.r.t. minimizing the residual, but the SD basis has some advantageous properties for the estimator. Since it is the estimated error that will govern the error control, the most efficient procedure is the one that results in the lowest error bound. The main contribution of this paper is further development of the previous work with a proposed combined basis constructed using both SD and POD modes together with an adaptive mode selection strategy. The performance of the combined basis is compared to (i) the pure SD basis and (ii) the pure POD basis via numerical examples. The examples show that it is possible to find a combination of SD/POD modes which is improved, i.e. it yields a smaller estimate, compared to the cases of pure SD or pure POD.

Reduced Basis Model Reduction of Parametrized Two—Phase Flow in Porous Media

2012 ◽  
Vol 45 (2) ◽  
pp. 722-727 ◽  
Author(s):  
Martin Drohmann ◽  
Bernard Haasdonk ◽  
Mario Ohlberger
Keyword(s):  
Porous Media ◽  
Model Reduction ◽  
Two Phase Flow ◽  
Flow In Porous Media ◽  
Phase Flow ◽  
Reduced Basis ◽  
Two Phase

scholarly journals A poro-viscoelastic substitute model of fine-scale poroelasticity obtained from homogenization and numerical model reduction

2020 ◽  
Vol 65 (4) ◽  
pp. 1063-1083 ◽  
Author(s):  
Ralf Jänicke ◽  
Fredrik Larsson ◽  
Kenneth Runesson
Keyword(s):  
Numerical Model ◽  
Model Reduction ◽  
Evolution Equations ◽  
Present Model ◽  
Scale Model ◽  
Reduced Basis ◽  
Pressure Fields ◽  
Linearly Independent ◽  
Macro Scale ◽  
Scale Fluctuation

AbstractNumerical model reduction is exploited for computational homogenization of the model problem of a poroelastic medium under transient conditions. It is assumed that the displacement and pore pressure fields possess macro-scale and sub-scale (fluctuation) parts. A linearly independent reduced basis is constructed for the sub-scale pressure field using POD. The corresponding reduced basis for the displacement field is constructed in the spirit of the NTFA strategy. Evolution equations that define an apparent poro-viscoelastic macro-scale model are obtained from the continuity equation pertinent to the RVE. The present model represents an extension of models available in literature in the sense that the pressure gradient is allowed to have a non-zero macro-scale component in the nested $$\hbox {FE}^2$$FE2 setting. The numerical results show excellent agreement between the results from numerical model reduction and direct numerical simulation. It was also shown that even 3D RVEs give tractable solution times for full-fledged $$\hbox {FE}^2$$FE2 computations.

scholarly journals Pyrolysis in Porous Media: Numerical model and parametric study.

2012 ◽  
Author(s):  
L. Romagnosi ◽  
N. Gascoin ◽  
E. El-Tabach ◽  
C. Strozzi ◽  
I. Fedioun ◽  
...  
Keyword(s):  
Porous Media ◽  
Numerical Model ◽  
Parametric Study

scholarly journals Electrified Powertrain with Multiple Planetary Gears and Corresponding Energy Management Strategy

Vehicles ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 341-356
Author(s):  
Daizy Rajput ◽  
Jose M. Herreros ◽  
Mauro S. Innocente ◽  
Joschka Schaub ◽  
Arash M. Dizqah
Keyword(s):  
Energy Consumption ◽  
Energy Management ◽  
Management Strategy ◽  
Hybrid Electric Vehicles ◽  
Mode Selection ◽  
Optimal Operation ◽  
Fourth Generation ◽  
Selection Strategy ◽  
Energy Management Strategy ◽  
Planetary Gears

Modern hybrid electric vehicles (HEVs) like the fourth generation of Toyota Prius incorporate multiple planetary gears (PG) to interconnect various power components. Previous studies reported that increasing the number of planetary gears from one to two reduces energy consumption. However, these studies did not compare one PG and two PGs topologies at their optimal operation. Moreover, the size of the powertrain components are not the same and hence the source of reduction in energy consumption is not clear. This paper investigates the effect of the number of planetary gears on energy consumption under optimal operation of the powertrain components. The powertrains with one and two PGs are considered and an optimal simultaneous torque distribution and mode selection strategy is proposed. The proposed energy management strategy (EMS) optimally distributes torque demands amongst the power components whilst also controlling clutches (i.e., mode selection). Results show that increasing from one to two PGs reduces energy consumption by 4%.

scholarly journals A numerical model for simulating two-phase flow through porous media

1989 ◽  
Vol 13 (5) ◽  
pp. 268-281 ◽  
Author(s):  
Anant R. Kukreti ◽  
Yatendra Rajapaksa
Keyword(s):  
Porous Media ◽  
Numerical Model ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Through Porous Media ◽  
Two Phase ◽  
Flow Through

Numerical Simulation of Insulin Depot Formation and Absorption in Subcutaneous Tissue Modeled as a Homogeneous Anisotropic Porous Media

2021 ◽  
Author(s):  
Michael Zedelmair ◽  
Abhijit Mukherjee
Keyword(s):  
Porous Media ◽  
Numerical Model ◽  
Insulin Pump ◽  
Subcutaneous Tissue ◽  
Saturated Porous Media ◽  
Anisotropic Porous Media ◽  
Effective Option ◽  
Computational Fluid Dynamics Cfd ◽  
Experimental Findings ◽  
Subcutaneous Adipose

Abstract In this study, a numerical model of the insulin depot formation and absorption in the subcutaneous adipose tissue is developed using the commercial Computational Fluid Dynamics (CFD) software. A better understanding of these mechanisms can be helpful in the development of new devices and cannula geometries as well as predicting the concentration of insulin in the blood. The injection method considered in this simulation is by the use of an insulin pump using a rapid acting U100 insulin analogue. The depot formation is analyzed running Bolus injections ranging from 5-15 units of insulin corresponding to 50-150µl. The insulin is injected into the subcutaneous tissue in the abdominal region. The tissue is modeled as a fluid saturated porous media. An anisotropic approach to define the tissue permeability is studied by varying the value of the porosity in parallel and perpendicular direction having an impact on the viscous resistance to the flow. Following recent experimental findings this configuration results in a disk shaped insulin depot. To be able to run the simulation over longer timeframes the depot formation model has been extended implementing the process of absorption of insulin from the depot. The developed model is then used to analyze the formation of the insulin depot in the tissue when using different flow rates and cannula geometries. The numerical model is an effective option to evaluate new cannula designs prior to the manufacturing and testing of prototypes, which are rather time consuming and expensive.

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