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

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

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

Laminar boundary layers behind detonation waves

1983 ◽  
Vol 387 (1793) ◽  
pp. 331-349 ◽  
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Boundary Layers ◽  
Flow Analysis ◽  
Time Dependent ◽  
Detonation Waves ◽  
Planar Geometry ◽  
Laminar Boundary Layers ◽  
Spherical Detonation ◽  
Layer Flow

New solutions are presented for non-stationary boundary layers induced by planar, cylindrical and spherical Chapman-Jouguet (C-J) detonation waves. The numerical results show that the Prandtl number ( Pr ) has a very significant influence on the boundary-layer-flow structure. A comparison with available time-dependent heat-transfer measurements in a planar geometry in a 2H 2 + O 2 mixture shows much better agreement with the present analysis than has been obtained previously by others. This lends confidence to the new results on boundary layers induced by cylindrical and spherical detonation waves. Only the spherical-flow analysis is given here in detail for brevity.

scholarly journals Global existence and decay estimates for nonlinear wave equations with space-time dependent dissipative term

2015 ◽  
Vol 12 (02) ◽  
pp. 249-276
Author(s):  
Tomonari Watanabe
Keyword(s):  
Global Existence ◽  
Nonlinear Wave ◽  
Wave Equations ◽  
Space Time ◽  
Time Dependent ◽  
Nonlinear Wave Equations ◽  
Energy Estimates ◽  
Space Region ◽  
Decay Estimates ◽  
Dissipative Term

We study the global existence and the derivation of decay estimates for nonlinear wave equations with a space-time dependent dissipative term posed in an exterior domain. The linear dissipative effect may vanish in a compact space region and, moreover, the nonlinear terms need not be in a divergence form. In order to establish higher-order energy estimates, we introduce an argument based on a suitable rescaling. The proposed method is useful to control certain derivatives of the dissipation coefficient.

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 Evolution of a domain wall in expanding universe: inflation and after it

2018 ◽  
Vol 191 ◽  
pp. 08004
Author(s):  
A.D. Dolgov ◽  
S.I. Godunov ◽  
A.S. Rudenko
Keyword(s):  
Domain Wall ◽  
Hubble Parameter ◽  
Domain Walls ◽  
Flat Space ◽  
Space Time ◽  
Time Dependent ◽  
Expanding Universe ◽  
Large Size ◽  
Dependent Parameter ◽  
Thick Domain Walls

We study the evolution of thick domain walls in the expanding universe. We have found that the domain wall evolution crucially depends on the time-dependent parameter C(t) = 1/(H(t)δ0)2, where H(t) is the Hubble parameter and δ0 is the width of the wall in flat space-time. For C(t) > 2 the physical width of the wall, a(t)δ(t), tends with time to constant value δ0, which is microscopically small. Otherwise, when C(t) ≤ 2, the wall steadily expands and can grow up to a cosmologically large size.

scholarly journals A New Design Method for Centrifugal Compressor Varied Diffusers

1989 ◽  
Author(s):  
Huang Xiaoyan ◽  
Wang Qinghuan ◽  
Zhang Chao
Keyword(s):  
Centrifugal Compressor ◽  
Design Method ◽  
Numerical Technique ◽  
Flow Analysis ◽  
Computer Code ◽  
Time Dependent ◽  
Code System ◽  
Extension Method ◽  
Operating Modes ◽  
Pressure Distributions

In order to develop a CAD computer code system for centrifugal compressor, a numerical technique for design and flow analysis of vaned diffusers has been introduced in this paper. The design of diffusers has been performed by a streamline extension method. The velocity and pressure distributions at design and off-design operating modes have been calculated by a time-dependent finite difference scheme and have been corrected by boundary layer calculations. The numerical results are compared with experimental measurements, and the agreement is satisfactory.

Sign in / Sign up

Export Citation Format

Share Document