scholarly journals Coupling reduced-order blood flow and cardiac models through energy-consistent strategies: modeling and discretization

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jessica Manganotti ◽  
Federica Caforio ◽  
François Kimmig ◽  
Philippe Moireau ◽  
Sebastien Imperiale
Keyword(s):  
Blood Flow ◽  
Numerical Experiments ◽  
Circulation Model ◽  
Arterial Segment ◽  
Reduced Order ◽  
Myosin Interaction ◽  
Cardiac Models ◽  
Energy Balances ◽  
Consistent Formulation

AbstractIn this work we provide a novel energy-consistent formulation for the classical 1D formulation of blood flow in an arterial segment. The resulting reformulation is shown to be suitable for the coupling with a lumped (0D) model of the heart that incorporates a reduced formulation of the actin-myosin interaction. The coupling being consistent with energy balances, we provide a complete heart-circulation model compatible with thermodynamics hence stable numerically and informative physiologically. These latter two properties are verified by numerical experiments.

Evaluating Effects of Observational Data Assimilation in General Ocean Circulation Model by Ensemble Kalman Filtering: Numerical Experiments with Synthetic Observations

2021 ◽  
pp. 50-66
Author(s):  
V. N. Stepanov ◽  
◽  
Yu. D. Resnyanskii ◽  
B. S. Strukov ◽  
A. A. Zelen’ko ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Observational Data ◽  
Ocean Circulation ◽  
Numerical Experiments ◽  
Turbulent Viscosity ◽  
Bottom Topography ◽  
Synthetic Data ◽  
Circulation Model ◽  
Ocean Model ◽  
Global Ocean

The quality of simulation of model fields is analyzed depending on the assimilation of various types of data using the PDAF software product assimilating synthetic data into the NEMO global ocean model. Several numerical experiments are performed to simulate the ocean–sea ice system. Initially, free model was run with different values of the coefficients of horizontal turbulent viscosity and diffusion, but with the same atmospheric forcing. The model output obtained with higher values of these coefficients was used to determine the first guess fields in subsequent experiments with data assimilation, while the model results with lower values of the coefficients were assumed to be true states, and a part of these results was used as synthetic observations. The results are analyzed that are assimilation of various types of observational data using the Kalman filter included through the PDAF to the NEMO model with real bottom topography. It is shown that a degree of improving model fields in the process of data assimilation is highly dependent on the structure of data at the input of the assimilation procedure.

Distributed Feedback Control of the Benjamin-Bona-Mahony-Burgers Equation by a Reduced-Order Model

2015 ◽  
Vol 5 (1) ◽  
pp. 61-74 ◽  
Author(s):  
Guang-Ri Piao ◽  
Hyung-Chun Lee
Keyword(s):  
Feedback Control ◽  
Numerical Experiments ◽  
Burgers Equation ◽  
Distributed Feedback ◽  
Reduced Order Model ◽  
Order Model ◽  
Reduced Order ◽  
Order Case ◽  
Functional Gain ◽  
Proper Orthogonal

AbstractA reduced-order model for distributed feedback control of the Benjamin-Bona-Mahony-Burgers (BBMB) equation is discussed. To retain more information in our model, we first calculate the functional gain in the full-order case, and then invoke the proper orthogonal decomposition (POD) method to design a low-order controller and thereby reduce the order of the model. Numerical experiments demonstrate that a solution of the reduced-order model performs well in comparison with a solution for the full-order description.

Numerical Modeling of Bioluminescence Distributions in the Coastal Ocean*

2003 ◽  
Vol 20 (7) ◽  
pp. 1060-1068 ◽  
Author(s):  
Igor Shulman ◽  
Steven H. D. Haddock ◽  
Dennis J. McGillicuddy ◽  
Jeffrey D. Paduan ◽  
W. Paul Bissett
Keyword(s):  
Hydrodynamic Model ◽  
Numerical Experiments ◽  
Flow Direction ◽  
Circulation Model ◽  
Velocity Fields ◽  
Monterey Bay ◽  
Resolution Model ◽  
Tracer Distribution ◽  
Fine Resolution ◽  
Initialization Procedure

Abstract Bioluminescence (BL) predictability experiments (predictions of the intensity, depth, and distance offshore of the BL maximum) were conducted using an advective–diffusive tracer model with velocities and diffusivities from a fine-resolution model of the Monterey Bay, California, area. For tracer initialization, observations were assimilated into the tracer model while velocities and diffusivities were taken from the hydrodynamic model and kept unchanged during the initialization process. This dynamic initialization procedure provides an equilibrium tracer distribution that is balanced with the velocity and diffusivity fields from the hydrodynamic model. This equilibrium BL distribution was used as the initial BL field for 3 days of prognostic calculations. Two cross-shore surveys of bioluminescence data conducted at two locations (north of the bay and inside the bay) were used in four numerical experiments designed to estimate the limits of bioluminescence predictions by tracers. The cross-shore sections extended to around 25 km offshore, they were around 30 m deep, and on average they were approximately 35 km apart from each other. Bioluminescence predictability experiments demonstrated a strong utility of the tracer model (combined with limited bioluminescence observations and with the output from a circulation model) in predicting (over a 72-h period and over 25–35-km distances) the location and intensity of the BL maximum. Analysis of the model velocity fields and observed and model-predicted bioluminesence fields shows that the BL maximum is located in the frontal area representing a strong reversal of flow direction.

scholarly journals Reduced order model for patient specific fluid transient simulation of blood flow in aortic cross

2019 ◽  
Vol 22 (sup1) ◽  
pp. S55-S57
Author(s):  
C. Shao ◽  
J. Tomasi ◽  
V. Morgenthaler ◽  
M. Lederlin ◽  
J. P. Verhoye ◽  
...  
Keyword(s):  
Blood Flow ◽  
Reduced Order Model ◽  
Transient Simulation ◽  
Patient Specific ◽  
Order Model ◽  
Reduced Order ◽  
Fluid Transient

scholarly journals The typhoon-induced drying of the Maritime Continent

2020 ◽  
Vol 117 (8) ◽  
pp. 3983-3988 ◽  
Author(s):  
Enrico Scoccimarro ◽  
Silvio Gualdi ◽  
Alessio Bellucci ◽  
Daniele Peano ◽  
Annalisa Cherchi ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Numerical Experiments ◽  
General Circulation ◽  
Circulation Model ◽  
Circulation Pattern ◽  
Maritime Continent ◽  
Global Circulation ◽  
Global Atmospheric Circulation ◽  
Definition Of ◽  
Convective Condensation

The Maritime Continent plays a role in the global circulation pattern, due to the energy released by convective condensation over the region which influences the global atmospheric circulation. We demonstrate that tropical cyclones contribute to drying the Maritime Continent atmosphere, influencing the definition of the onset of the dry season. The process was investigated using observational data and reanalysis. Our findings were confirmed by numerical experiments using low- and high-resolution versions of the CMCC-CM2 General Circulation Model contributing to the HighResMIP CMIP6 effort.

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