Temat: turbulence modeling

Skocz do pozycji: 1.

Tytuł:: Beyond one-point turbulence closures
Autorzy:: Wacławczyk, M.
Tematy:: turbulence
turbulence modeling
multipoint velocity statistic; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/175558.pdf Link otwiera się w nowym oknie
Opis:: The paper concerns statistical description of turbulence in terms of multipoint velocity moments. A literature survey on possible multipoint turbulence closures and their future perspective is provided. We ﬁrst consider the transport equations for two-point velocity statistics and their one-point limit. Another form of turbulence description, in terms of multipoint probability density functions is also introduced.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 2.

Tytuł:: Performance of three turbulence models in 3D flow investigation for a 1.5-stage turbine
Autorzy:: Karczewski, M.
Błaszczak, J.
Tematy:: turbulence modeling
numerical research
low-pressure turbine; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1943250.pdf Link otwiera się w nowym oknie
Opis:: The object of this study was to investigate the flow phenomena in a cold air turbine built at the Institute of Jet Propulsion and Turbomachinery at Aachen Technical University (IST RWTH Aachen, Germany). The said turbine had been studied previously both experimentally and numerically on an IST’s flow solver called Panta Rhei. Since that time certain improvements, computational-wise, have been implemented in the code. In order to test them, new simulation runs were conducted. The detailed studies of the measured and computed flow angles as well as a flow velocity analysis are the means for this evaluation.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 3.

Tytuł:: On general-purpose turbulence models in CFD
Autorzy:: Pozorski, J.
Tematy:: computational fluid dynamics
turbulence modeling
Reynolds-averaged approaches; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/175545.pdf Link otwiera się w nowym oknie
Opis:: The computational fluid dynamics (CFD) tools for various flow problems have become widespread nowadays, yet their use still needs attention and care. In particular, turbulence models are often a crucial part of flow computations undertaken with various software packages, either commercial, open-source or in-house. In the paper, an overview of available model categories is provided, together with some discussion of their advantages or drawbacks with respect to flow cases of interest.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 4.

Tytuł:: Analysis of non-equidistant baffle spacing in a small shell and tube heat exchanger
Autorzy:: Aziz, Abdullah
Rehman, Shafique
Tematy:: thermal distribution
baffle spacing
heat exchanger
turbulence modeling
CFD study; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/240423.pdf Link otwiera się w nowym oknie
Opis:: Most of the formulations regarding the characteristics of a shell and tube heat exchanger have a common assumption; namely that the baffle plates are equidistant. This assumption fails to cater the real world scenario for defective baffles as the alteration in a shell and tube heat exchanger invalidates the equidistant baffle spacing of the plates. In this regard, a small six baffles heat exchanger was modeled in the computational fluid dynamics software package and studied by removing each baffle plate one at a time. Effect of removing each baffle plate on the temperature, pressure, heat transfer coefficient, and total heat transfer rate was recorded. It was observed that variation in the pressure drop for the same number of baffle plates varies along the axial order of the plates. The change in pressure drop due to the removal of the baffle plate near the inlet and the outlet was lowest and reaches a maximum in the axial center. It was also found that the plates below the radial center contribute higher towards the overall heat transfer as compared to those above.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 5.

Tytuł:: Modeling of rough wall boundary layers with an intermittency transport model
Autorzy:: Elsner, W.
Warzecha, P.
Tematy:: surface roughness
boundary layer
turbulence
transition modeling; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1943210.pdf Link otwiera się w nowym oknie
Opis:: The paper presents a new extension of the -Ret model to account for both the laminar-turbulent transition and the surface roughness. The new modeling approach takes into account the pressure gradient, turbulence intensity and roughness height and density. In the transition region both the intermittency transport equation and the momentum thickness Reynolds number Ret transport equation, supplemented by the correlation of Stripf et al. (2009) suitable for rough wall boundary layers are used. An additional modification of the SST turbulence model allows for modeling a full turbulent boundary layer over surfaces with sand roughness. A comprehensive validation of the new method using transitional and fully turbulent test cases was performed. Flat plate data with a zero and non-zero pressure gradient test case as well as a high pressure turbine blade case were used for this purpose The studies proved that the new modeling approach appeared to be sufficiently precise and enabled a qualitative prediction of the boundary layer development for the tested flow configurations.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 6.

Tytuł:: Parabolic turbulence k-epsilon model with applications in fluid flows through permeable media
Autorzy:: Oliveira, Hermenegildo Borges de
Tematy:: turbulence
k-epsilon modeling
permeable media
existence; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:: https://bibliotekanauki.pl/articles/29519477.pdf Link otwiera się w nowym oknie
Opis:: In this work, we study a one-equation turbulence k-epsilon model that governs fluid flows through permeable media. The model problem under consideration here is derived from the incompressible Navier-Stokes equations by the application of a time-averaging operator used in the k-epsilon modeling and a volume-averaging operator that is characteristic of modeling unsteady porous media flows. For the associated initial- and boundary-value problem, we prove the existence of suitable weak solutions (average velocity field and turbulent kinetic energy) in the space dimensions of physics interest.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 7.

Tytuł:: Numerical modeling of tsunami wave destruction and turbulent mixing at tsunami wave clash on the shore
Autorzy:: Kshevetskii, S.
Vereshchagina, I.
Tematy:: tsunami
stratified fluid
internal wave
numerical modeling
wave breakdown
mixing
turbulence
ocean; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1938595.pdf Link otwiera się w nowym oknie
Opis:: A numerical model of propagation of internal gravity waves in a stratified medium is applied to the problem of tsunami wave run-up onto a shore. In the model, the ocean and the atmosphere are considered as a united continuum in which the density varies with height with a saltus at the water-air interface. The problem solution is sought as a generalized (weak) solution; such a mathematical approach automatically ensures correct conditions of matching of the solutions used on a water-air interlayer. The density stratification in the ocean and in the atmosphere is supposed to be described with an exponential function, but in the ocean a scale of the density stratification takes a large value and the density changes slightly. The initial wave running to a shore is taken in the form of a long solitary wave. The wave evolution is simulated with consideration of the time-varying vertical wave structure. Near the shore, the wave breaks down, and intensive turbulent mixing develops in the water thickness. The wave breakdown effect depends on the bottom shape. In the case when the bottom slope is small and the inshore depth grows slowly with the distance from the shore, mixing happens only in the upper stratum of the fluid due to the formation of a quiet region near the bottom. When the bottom slope takes a sufficiently large value, the depth where fluid mixing takes place goes down up to 50 meters. The developed model shows that the depth of the mixing effects strongly depends on the bottom shape, and the model may be useful for investigation of the impact strong gales and hurricanes on the coastline and beaches.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 8.

Tytuł:: Numerical Simulation of Turbulence Flows in Shear Layer
Symulacja numeryczna płynięcia turbulentnego w warstwie ścinanej
Autorzy:: Fortova, S. V.
Tematy:: mathematical modeling
shear layers
energy cascade
turbulence
modelowanie matematyczne
warstwa ścinana
płynięcie turbulentne; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/352136.pdf Link otwiera się w nowym oknie
Opis:: For various problems of continuum mechanics described by the equations of hyperbolic type, the comparative analysis of scenarios of development of turbulent flows in shear layers is carried out. It is shown that the development of the hydrodynamic instabilities leads to a vortex cascade that corresponds to the development stage of the vortices in the energy and the inertial range during the transition to the turbulent flow stage. It is proved that for onset of turbulence the spatial problem definition is basic. At the developed stage of turbulence the spectral analysis of kinetic energy is carried out and the Kolmogorov “-5/3” power law is confirmed.
W pracy dokonano analizy porównawczej rozwoju przepływu turbulentnego w warstwach ścinanych dla wielu problemów dotyczących mechaniki ośrodków ciągłych opisanych przez równania typu hiperbolicznego. Wykazano, że rozwój niestabilności hydrodynamicznych prowadzi do cyklicznych zawirowań podczas przejścia do stadium przepływu turbulentnego. Udokumentowano, że dla wyjaśnienia mechanizmu pojawienia się turbulencji kluczowe znaczenie ma przestrzenna analiza problemu. Przeprowadzono analizę widmową energii kinetycznej dla zaawansowanego stadium przepływu turbulentnego oraz potwierdzono wartość wykładnika “-5/3” w równaniu Kołmogorowa.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Informacja

Wyszukujesz frazę "turbulence modeling" wg kryterium: Temat