Temat: circular cylinder - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Experimental study of thermal effects in cooling a circular cylinder in lock-on conditions
Autorzy:: Gnatowski, Adam
Sosnowski, Marcin
Pajdak, Anna
Sobczyk, Jacek
Tematy:: thermal effects
circular cylinder
efekty termiczne
okrągły cylinder; Pokaż więcej
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Powiązania:: https://bibliotekanauki.pl/articles/103023.pdf Link otwiera się w nowym oknie
Opis:: The paper presents a simple method for determining the phenomenon of unsteady thermal effects in cooling a circular cylinder. The research has been undertaken in order to explain the thermoaerodynamic processes, which are characterized by the turbulent structure of the flow around a stationary rigid heated cylinder cooled by the oscillating flow. The forced convection of heat occurs in the presence of not only random velocity fluctuation but also in the conditions of periodical forms of motion caused mainly by the process of vortex going down and externally formed oscillations of the inflow. The Nusselt number was evaluated at various frequencies of disturbances of the inlet velocity field, especially in lock-on conditions, on the surface of the circular cylinder versus angular location Θ = 0 180°. The subject of the study focuses on the analysis of current state of the problem and development of the method to measure and calculate basic values that characterize unsteady processes of thermal effects on the circular cylinder surface and indication of the directions of further work.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Numerical simulations of linearly stratified flow past submerged bodies
Autorzy:: Ma, W.
Li, Y.
Ding, Y.
Hu, K.
Lan, L.
Tematy:: stratified flow
circular cylinder
internal wave
Suboff
equation of state; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/259150.pdf Link otwiera się w nowym oknie
Opis:: In this study, a methodology was presented to predict density stratified flows in the near-field of submerged bodies. The energy equation in temperature form was solved coupled with momentum and mass conservation equations. Linear stratification was achieved by the definition of the density as a function of temperature. At first, verifications were performed for the stratified flows passing a submerged horizontal circular cylinder, showing excellent agreement with available experimental data. The ability of the method to cope with variable density was demonstrated. Different turbulence models were used for different Re numbers and flow states. Based on the numerical methods proposed in this paper, the stratified flow was studied for the real scale benchmark DAPRA Suboff submarine. The approach used the VOF method for tracing the free surface. Turbulence was implemented with a k − ω based Detached Eddy Simulation (DES) approach. The effects of submarine speed, depth and density gradient on the free surface wave pattern were quantitatively analyzed. It was shown that, with the increasing of the speed of the submarine, the wavelength and wave height of the free surface wave were gradually increasing. The wave height of the free surface wave was gradually reduced as the submarine’s depth increased. Relative to the speed and submarine depth, the changes of the gradient density gradient have negligible effects on the free surface wave field.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Unconfined laminar nanofluid flow and heat transfer around a rotating circular cylinder in the steady regime
Autorzy:: Bouakkaz, R.
Salhi, F.
Khelili, Y.
Quazzazi, M.
Talbi, K.
Tematy:: nanofluid
rotating circular cylinder
forced convection
steady regime
obracanie
cylinder okrągły
konwekcja wymuszona; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/240108.pdf Link otwiera się w nowym oknie
Opis:: In this work, steady flow-field and heat transfer through a copper-water nanofluid around a rotating circular cylinder with a constant nondimensional rotation rate α varying from 0 to 5 was investigated for Reynolds numbers of 5–40. Furthermore, the range of nanoparticle volume fractions considered is 0–5%. The effect of volume fraction of nanoparticles on the fluid flow and heat transfer characteristics are carried out by using a finite-volume method based commercial computational fluid dynamics solver. The variation of the local and the average Nusselt numbers with Reynolds number, volume fractions, and rotation rate are presented for the range of conditions. The average Nusselt number is found to decrease with increasing value of the rotation rate for the fixed value of the Reynolds number and volume fraction of nanoparticles. In addition, rotation can be used as a drag reduction technique.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Random vortex method in numerical analysis of 2D flow around circular cylinder
Autorzy:: Kostecki, S.
Tematy:: vorticity
vortex method
flow instability
circular cylinder
boundary element method; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/178682.pdf Link otwiera się w nowym oknie
Opis:: A combination of the vortex method and the boundary element method is used here to predict the two-dimensional flow field around a circular cylinder. Cylindrical structures experience strong hydrodynamic loading, due to vortex detachment from the both sides of cylinder during the flow. Thus, the practical meaning of such calculation is significant particularly in offshore oil and gas engineering as well as in the bridge and hydraulic structure engineering. This paper presents the mathematical formulation of the vortex method for the velocity and vorticity field calculation. The calculated velocity and vorticity fields are then used to predict the pressure distribution on the cylinder surface by the boundary element method. The resulting pressure on the cylinder, the Strouhal number and the length of the base recirculation zone are compared with solutions of other numerical methods and experiments, and a good agreement is achieved.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Unconfined laminar nanofluid flow and heat transfer around a rotating circular cylinder dissipating uniform heat flux in the steady regime
Autorzy:: Bouakkaz, Rafik
Ouali, Abded El Ouahed
Khelili, Yacine
Faouzi, Salhi
Tiauiri, Ilyes
Tematy:: copper nanoparticles
rotating circular cylinder
dissipating uniform heat flux
steady regime; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/240386.pdf Link otwiera się w nowym oknie
Opis:: In this work, steady flow-field and heat transfer through a copper-water nanofluid around a rotating circular cylinder, dissipating uniform heat flux, with a constant non-dimensional rotation rate varying from 0 to 5 was investigated numerically using a finite-volume method for Reynolds numbers from the range 10–40. Furthermore, the range of nanoparticle volume fractions considered is 0–5%. The variation of the local and the average Nusselt numbers with Reynolds number, volume fractions, and rotation rate are presented for the range of conditions. The average Nusselt number is found to increase with increasing the nanoparticle volume fractions and decrease with increasing value of the rotation rate.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Numerical analysis of oscillating flow around a cylinder
Autorzy:: Gnatowska, R.
Tematy:: mathematical modelling
unsteady flow phenomena
circular cylinder
modelowanie matematyczne
niestacjonarne zjawiska przepływowe
cylinder kołowy; Pokaż więcej
Wydawca:: Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Powiązania:: https://bibliotekanauki.pl/articles/122556.pdf Link otwiera się w nowym oknie
Opis:: This paper presents the numerical model of the measuring stand - the wind tunnel, in which there is fixed a cylinder with a turbulent inlet oscillating stream. The aim of this work is the juxtaposition and comparison of characteristic values concerning the oscillating turbulent flow around the cylinder, obtained from the experiment conducted in the wind tunnel at the Institute of Thermal Machinery with the data obtained as a result of numerical modelling of unsteady phenomena. The model discussed in this paper was created using a commercial program ANSYS FLUENT that is used for mathematical modelling of flow and heat transfer processes. The expected outcome of this study is possibility of the numerical modelling of the stand concerning the analogous unsteady flows without significant investment of time. Comparison of longitudinal and transverse velocity profiles in aerodynamic wake and the pressure coefficient distributions on the cylinder surface show similarities between experimental and numerical studies.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Influence of wind structure and aspect ratio of circular cylinders on mean wind pressure coefficient
Autorzy:: Lipecki, T
Jamińska, P.
Tematy:: wind tunnel
mean wind pressure coefficient
circular cylinder
wind structure
aspect ratio; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1933975.pdf Link otwiera się w nowym oknie
Opis:: The paper presents analyses of the mean wind pressure coefficient distribution on the surfaces of circular cylinders. The experiment was performed in a boundary layer wind tunnel in the Wind Engineering Laboratory in Cracow, Poland. Three models were examined in the wind tunnel. The influence of the aspect ratio and wind parameters (mean wind speed profile, turbulence intensity profile, power spectral density functions) on the mean wind pressure coefficient distribution and its standard deviation was considered during the tests.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Non-simple elastic materials with double porosity structure
Autorzy:: De Cicco, S.
Tematy:: strain-gradient theory
porous solids
chiral materials
torsion of a circular cylinder; Pokaż więcej
Wydawca:: Instytut Podstawowych Problemów Techniki PAN
Powiązania:: https://bibliotekanauki.pl/articles/38695685.pdf Link otwiera się w nowym oknie
Opis:: This paper is concerned with a strain gradient theory of elastic materials that have a double porosity structure. Firstly, we present the basic equations and the boundary conditions of the nonlinear theory. Then, we derive the equations of the linear theory and present the constitutive equations for chiral materials. The theory is applied to study the deformation of a chiral cylinder. The materials with a double porosity are of interest in geophysics and in mechanics of bone.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Numerical simulation of forced convection of nanofluid around a circular cylinder
Autorzy:: Korib, Kamel
Ihaddadene, Nabila
Bouakkaz, Rafik
Khelili, Yacine
Tematy:: copper nanoparticles
heat transfer
circular cylinder
steady regime
walec kołowy
wymiana ciepła
nanocząstki miedzi; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/240282.pdf Link otwiera się w nowym oknie
Opis:: In this study a steady flow-field and heat transfer through a copper-water nanofluid around a circular cylinder, under the influence of both the standard thermal boundary conditions, i.e., uniform heat flux and constant wall temperature) was investigated numerically by using a finitevolume method for Reynolds numbers from the range 10–40. Furthermore, the range of nanoparticle volume fractions considered is 0–5%. The variation of the local and the average Nusselt numbers with Reynolds number, and volume fractions are presented for the range of conditions. The average Nusselt number is found to increase with increasing the nanoparticle volume fractions.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Wpływ struktury wiatru na rozkład współczynnika ciśnienia na powierzchni modelu o przekroju kołowym o średnicy 20 cm
Wind structure influence on pressure coefficient distribution on the surface of circular cylinder of the diameter 20 cm
Autorzy:: Lipecki, T.
Bęc, J.
Błazik-Borowa, E.
Tematy:: tunel aerodynamiczny
współczynnik ciśnienia
walec kołowy
struktura wiatru
wind tunnel
pressure coefficient
circular cylinder
wind structure; Pokaż więcej
Wydawca:: Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Powiązania:: https://bibliotekanauki.pl/articles/391107.pdf Link otwiera się w nowym oknie
Opis:: W pracy przedstawiono wyniki i analizę badań modelowych przeprowadzonych w tunelu aerodynamicznym w odniesieniu do opływu pojedynczego walca kołowego. Wyniki dotyczą zmian wartości zredukowanego współczynnika średniego ciśnienia na powierzchni modelu oraz jego odchylenia standardowego. W badaniach analizowano 6 przypadków struktury napływającego wiatru opisanej za pomocą funkcji pionowego profilu średniej prędkości wiatru, pionowego profilu intensywności turbulencji oraz funkcji gęstości widmowej mocy. Wysokość badanego modelu oraz jego średnica wynosiły odpowiednio H = 100 cm i D = 20 cm.
The paper deals with results and analyses of the model investigations which were performed in wind tunnel and were focused on the flow around single circular cylinder. Presented results are related to variations in the distribution of the normalized mean pressure coefficient on the surface of the model as well as its standard deviation. Sic cases of the approaching flow were taken into consideration. The flow was described by vertical profile of the mean wind speed, vertical profile of the intensity of turbulence, and power spectral density functions. The height and dimension of the model were respectively equal: H = 100 cm, D = 20 cm. Selected results of measurements have been shown in the paper as the effect of these experiments.
Dostawca treści:: Biblioteka Nauki

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