scholarly journals Heart valve flow computation with the integrated Space–Time VMS, Slip Interface, Topology Change and Isogeometric Discretization methods

2017 ◽  
Vol 158 ◽  
pp. 176-188 ◽  
Author(s):  
Kenji Takizawa ◽  
Tayfun E. Tezduyar ◽  
Takuya Terahara ◽  
Takafumi Sasaki
Keyword(s):  
Heart Valve ◽  
Space Time ◽  
Topology Change ◽  
Discretization Methods ◽  
Flow Computation ◽  
Isogeometric Discretization

scholarly journals Heart valve isogeometric sequentially-coupled FSI analysis with the space–time topology change method

2020 ◽  
Vol 65 (4) ◽  
pp. 1167-1187 ◽  
Author(s):  
Takuya Terahara ◽  
Kenji Takizawa ◽  
Tayfun E. Tezduyar ◽  
Yuri Bazilevs ◽  
Ming-Chen Hsu
Keyword(s):  
Fluid Mechanics ◽  
Heart Valve ◽  
Complex Geometry ◽  
Space Time ◽  
Multiscale Methods ◽  
Topology Change ◽  
Mesh Resolution ◽  
Flow Through ◽  
Isogeometric Discretization ◽  
Variational Multiscale Methods

AbstractHeart valve fluid–structure interaction (FSI) analysis is one of the computationally challenging cases in cardiovascular fluid mechanics. The challenges include unsteady flow through a complex geometry, solid surfaces with large motion, and contact between the valve leaflets. We introduce here an isogeometric sequentially-coupled FSI (SCFSI) method that can address the challenges with an outcome of high-fidelity flow solutions. The SCFSI analysis enables dealing with the fluid and structure parts individually at different steps of the solutions sequence, and also enables using different methods or different mesh resolution levels at different steps. In the isogeometric SCFSI analysis here, the first step is a previously computed (fully) coupled Immersogeometric Analysis FSI of the heart valve with a reasonable flow solution. With the valve leaflet and arterial surface motion coming from that, we perform a new, higher-fidelity fluid mechanics computation with the space–time topology change method and isogeometric discretization. Both the immersogeometric and space–time methods are variational multiscale methods. The computation presented for a bioprosthetic heart valve demonstrates the power of the method introduced.

scholarly journals Ventricle-valve-aorta flow analysis with the Space–Time Isogeometric Discretization and Topology Change

2020 ◽  
Vol 65 (5) ◽  
pp. 1343-1363 ◽  
Author(s):  
Takuya Terahara ◽  
Kenji Takizawa ◽  
Tayfun E. Tezduyar ◽  
Atsushi Tsushima ◽  
Kensuke Shiozaki
Keyword(s):  
Flow Analysis ◽  
Space Time ◽  
Topology Change ◽  
And Topology ◽  
Isogeometric Discretization

scholarly journals Space–time VMS flow analysis of a turbocharger turbine with isogeometric discretization: computations with time-dependent and steady-inflow representations of the intake/exhaust cycle

2019 ◽  
Vol 64 (5) ◽  
pp. 1403-1419 ◽  
Author(s):  
Yuto Otoguro ◽  
Kenji Takizawa ◽  
Tayfun E. Tezduyar ◽  
Kenichiro Nagaoka ◽  
Reha Avsar ◽  
...  
Keyword(s):  
Flow Analysis ◽  
Space Time ◽  
Time Dependent ◽  
Isogeometric Discretization

Heart Valve Flow Analysis with Isogeometric Discretization and Resolved Jet Flow Near Leaflet Surfaces

2017 ◽  
Vol 2017 (0) ◽  
pp. J0230305
Author(s):  
Takuya TERAHARA ◽  
Takafumi SASAKI ◽  
Kenji TAKIZAWA ◽  
Tayfun E. TEZDUYAR
Keyword(s):  
Heart Valve ◽  
Flow Analysis ◽  
Jet Flow ◽  
Isogeometric Discretization

TOPOLOGY CHANGE AND SIGNATURE CHANGE IN NON-LINEAR FIRST-ORDER GRAVITY

2007 ◽  
Vol 04 (04) ◽  
pp. 647-667 ◽  
Author(s):  
ANDRZEJ BOROWIEC ◽  
MAURO FRANCAVIGLIA ◽  
IGOR VOLOVICH
Keyword(s):  
Space Time ◽  
Relativistic Cosmology ◽  
Lagrangian Formalism ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Topology Change ◽  
First Order ◽  
Signature Change ◽  
Nonlinear Lagrangians ◽  
Momentum Complex

We show that different topologies of a space-time manifold and different signatures of its metric can be encompassed into a single Lagrangian formalism, provided one adopts the first-order (Palatini) formulation and relies on nonlinear Lagrangians, that were earlier shown to produce, in the generic case, universality of Einstein field equations and of Komar's energy-momentum complex as well. An example in Relativistic Cosmology is provided.

Patient-Specific Aorta Flow Analysis with the Space-Time VMS Method and Isogeometric Discretization

2017 ◽  
Vol 2017 (0) ◽  
pp. J0230303
Author(s):  
Hiroaki UCHIKAWA ◽  
Takuya TERAHARA ◽  
Takafumi SASAKI ◽  
Kenji TAKIZAWA ◽  
Tayfun E. TEZDUYAR
Keyword(s):  
Flow Analysis ◽  
Space Time ◽  
Patient Specific ◽  
Isogeometric Discretization

scholarly journals Wind Turbine and Turbomachinery Computational Analysis with the ALE and Space-Time Variational Multiscale Methods and Isogeometric Discretization

2020 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Yuri Bazilevs ◽  
Kenji Takizawa ◽  
Tayfun E. Tezduyar ◽  
Ming-Chen Hsu ◽  
Yuto Otoguro ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Computational Analysis ◽  
Vertical Axis ◽  
Space Time ◽  
Multiscale Methods ◽  
Arbitrary Lagrangian Eulerian ◽  
Variational Multiscale ◽  
Creative Commons ◽  
Isogeometric Discretization

The challenges encountered in computational analysis of wind turbines and turbomachinery include turbulent rotational flows, complex geometries, moving boundaries and interfaces, such as the rotor motion, and the fluid-structure interaction (FSI), such as the FSI between the wind turbine blade and the air. The Arbitrary Lagrangian-Eulerian (ALE) and Space-Time (ST) Variational Multiscale (VMS) methods and isogeometric discretization have been effective in addressing these challenges. The ALE-VMS and ST-VMS serve as core computational methods. They are supplemented with special methods like the Slip Interface (SI) method and ST Isogeometric Analysis with NURBS basis functions in time. We describe the core and special methods and present, as examples of challenging computations performed, computational analysis of horizontal and vertical-axis wind turbines and flow-driven This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

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