Numerical simulation of the divergent flow regime in a circular contraction flow of a viscoelastic fluidTheoretical and Computational Fluid Dynamics - Tập 5 - Trang 33-48 - 1993
Martien A. Hulsen
A numerical method is used to study the influence of inertia and elongational
properties on the vortex growth in the flow of a viscoelastic fluid through a
four-to-one contraction. It appears that the vortex growth regime and the
divergent flow regime, which are observed in experiments for some fluids, can be
found for a choice of the material parameters where both the elongational
stresses and th... hiện toàn bộ
An experimental and numerical study of the influence of viscosity on the behavior of dam-break flowTheoretical and Computational Fluid Dynamics - Tập 35 - Trang 345-362 - 2021
Le-Quyen Nguyen-Thi, Viet-Dung Nguyen, Xavier Pierens, Patrice Coorevits
In this paper, experimental and numerical methods are presented to investigate
the dam-break flow in a horizontal rectangular section flume. In the
experimental part of the research, different configurations have been tested:
dry flume and the presence of shallow ambient water downstream with varied
depth. In addition, experiments with viscosity changes in the fluid have been
conducted. Numericall... hiện toàn bộ
Exact transport equation for eddy diffusivity in turbulent shear flowTheoretical and Computational Fluid Dynamics - Tập 27 - Trang 651-664 - 2012
Fujihiro Hamba
Two-equation models that treat the transport equations for two variables are
typical models for the Reynolds-averaged Navier–Stokes equation. Compared to the
equation for the turbulent kinetic energy, the equation for the second variable
such as the dissipation rate does not have a theoretical analogue. In this work,
the exact transport equation for the eddy diffusivity was derived and examined
fo... hiện toàn bộ
Convectively coupled wave–environment interactionsTheoretical and Computational Fluid Dynamics - Tập 27 - Trang 513-532 - 2012
Samuel N. Stechmann, Andrew J. Majda, Dmitri Skjorshammer
In the tropical atmosphere, waves can couple with water vapor and convection to
form large-scale coherent structures called convectively coupled waves (CCWs).
The effects of water vapor and convection lead to CCW–mean flow interactions
that are different from traditional wave–mean flow interactions in many ways.
CCW–mean flow interactions are studied here in two types of models: a multiscale
model... hiện toàn bộ
A characteristic dynamic mode decompositionTheoretical and Computational Fluid Dynamics - Tập 33 - Trang 281-305 - 2019
Jörn Sesterhenn, Amir Shahirpour
Temporal or spatial structures are readily extracted from complex data by modal
decompositions like proper orthogonal decomposition (POD) or dynamic mode
decomposition (DMD). Subspaces of such decompositions serve as reduced order
models and define either spatial structures in time or temporal structures in
space. On the contrary, convecting phenomena pose a major problem to those
decompositions. ... hiện toàn bộ
Numerical realization of helical vortices: application to vortex instabilityTheoretical and Computational Fluid Dynamics - Tập 34 - Trang 1-20 - 2019
Mattias Brynjell-Rahkola, Dan S. Henningson
The need to numerically represent a free vortex system arises frequently in
fundamental and applied research. Many possible techniques for realizing this
vortex system exist but most tend to prioritize accuracy either inside or
outside of the vortex core, which therefore makes them unsuitable for a
stability analysis considering the entire flow field. In this article, a simple
method is presented ... hiện toàn bộ
A locally induced homoclinic motion of a vortex filamentTheoretical and Computational Fluid Dynamics - Tập 24 - Trang 383-387 - 2009
Makoto Umeki
An exact homoclinic solution of the Da Rios–Betchov equation is derived using
the Hirota bilinear equation. This solution describes unsteady motions of a
linearly unstable helical or wound closed filament under the localized induction
approximation.
Explosive instability of geostrophic vortices. Part 1: baroclinic instabilityTheoretical and Computational Fluid Dynamics - Tập 24 - Trang 125-130 - 2009
Xavier Carton, Glenn R. Flierl, Xavier Perrot, Thomas Meunier, Mikhail A. Sokolovskiy
In a quasi-geostrophic model, we study the baroclinic instability of a two-layer
vortex. The singular unstable modes for potential vorticity anomalies are
compared with the classical normal modes. Short-time singular modes are
explosively unstable and, at short times, depend only on the baroclinic
component of the flow. As time progresses, they evolve towards the normal modes
and their sensitivity... hiện toàn bộ