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

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 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.

RESEARCH OF METHODS FOR DECREASE OF THE CAPACITANCE RATIO IN THE STW-RESONATORS

2021 ◽  
pp. 43-56
Author(s):  
S. A. Dobershtein ◽  
N. M. Zhilin ◽  
I. V. Veremeev
Keyword(s):  
Experimental Data ◽  
Quality Factor ◽  
Quality Factors ◽  
Topology Change ◽  
Series Connection ◽  
Capacitance Ratio ◽  
And Topology

This paper presents the research of methods for decrease of the capacitance ratio in the STW-resonators without significant degradation of the quality factor by use of the external inductors and topology change: IDT division on parts and their series connection. The calculated and experimental data are presented for 416 MHz and 766 MHz STW-resonators with quality factors Q = 7000–7978. The capacitance ratio has been reduced from 1200 to 301.

Space–Time Gradient Method for Unsteady Bladerow Interaction—Part II: Further Validation, Clocking, and Multidisturbance Effect

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
L. He ◽  
J. Yi ◽  
P. Adami ◽  
L. Capone
Keyword(s):  
Case Studies ◽  
Flow Analysis ◽  
Space Time ◽  
Inlet Temperature ◽  
Turbine Stage ◽  
Two Stage ◽  
Transonic Compressor ◽  
Surface Time ◽  
Blade Row ◽  
Speed Up

For efficient and accurate unsteady flow analysis of blade row interactions, a space–time gradient (STG) method has been proposed. The development is aimed at maintaining as many modeling fidelities (the interface treatment in particular) of a direct unsteady time-domain method as possible while still having a significant speed-up. The basic modeling considerations, main method ingredients and some preliminary verification have been presented in Part I of the paper. Here in Part II, further case studies are presented to examine the capability and applicability of the method. Having tested a turbine stage in Part I, here we first consider the applicability and robustness of the method for a three-dimensional (3D) transonic compressor stage under a highly loaded condition with separating boundary layers. The results of the STG solution compare well with the direct unsteady solution while showing a speed up of 25 times. The method is also used to analyze rotor–rotor/stator–stator interferences in a two-stage turbine configuration. Remarkably, for stator–stator and rotor–rotor clocking analyses, the STG method demonstrates a significant further speed-up. Also interestingly, the two-stage case studies suggest clearly measurable clocking dependence of blade surface time-mean temperatures for both stator–stator clocking and rotor–rotor clocking, though only small efficiency variations are shown. Also validated and illustrated is the capacity of the STG method to efficiently evaluate unsteady blade forcing due to the rotor–rotor clocking. Considerable efforts are directed to extending the method to more complex situations with multiple disturbances. Several techniques are adopted to decouple the disturbances in the temporal terms. The developed capabilities have been examined for turbine stage configurations with inlet temperature distortions (hot streaks), and for three blade-row turbine configurations with nonequal blade counts. The results compare well with the corresponding direct unsteady solutions.

scholarly journals Quantum gravity as a multitrace matrix model

2017 ◽  
Vol 32 (31) ◽  
pp. 1750180
Author(s):  
Badis Ydri ◽  
Cherine Soudani ◽  
Ahlam Rouag
Keyword(s):  
Quantum Gravity ◽  
Matrix Models ◽  
Large Class ◽  
Matrix Model ◽  
Two Dimensions ◽  
Two Dimensional ◽  
Topology Change ◽  
New Model ◽  
And Topology ◽  
Emergent Geometry

We present a new model of quantum gravity as a theory of random geometries given explicitly in terms of a multitrace matrix model. This is a generalization of the usual discretized random surfaces of two-dimensional quantum gravity which works away from two dimensions and captures a large class of spaces admitting a finite spectral triple. These multitrace matrix models sustain emergent geometry as well as growing dimensions and topology change.

Geometry and Topology Change in Complex Systems

2008 ◽  
pp. 305-424
Author(s):  
Vladimir G. Ivancevic ◽  
Tijana T. Ivancevic
Keyword(s):  
Complex Systems ◽  
Topology Change ◽  
And Topology
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