共查询到20条相似文献,搜索用时 31 毫秒
1.
Mustafa Barri George K. El Khoury Helge I. Andersson Bjrnar Pettersen 《国际流体数值方法杂志》2010,64(7):777-792
Direct numerical simulation (DNS) has been performed to study the channel flow over a backward‐facing step at a Reynolds number Reb=5600 based on the step height h and the inflow bulk velocity Ub. A dynamic method has been used in order to generate realistic turbulent inflow conditions. The results upstream of the step compared well with the fully developed channel flow. Downstream of the step our results show excellent agreement with experimental data. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
2.
Scalar transport from a point source in flows over wavy walls 总被引:1,自引:0,他引:1
Simultaneous measurements of the velocity and concentration field in fully developed turbulent flows over a wavy wall are
described. The concentration field originates from a low-momentum plume of a passive tracer. PLIF and digital particle image
velocimetry are used to make spatially resolved measurements of the structure of the scalar distribution and the velocity.
The measurements are performed at three different Reynolds numbers of Re
b = 5,600, Re
b = 11,200 and Re
b = 22,400, respectively, based on the bulk velocity u
b and the total channel height 2h. The velocity field and the scalar field are investigated in a water channel with an aspect ratio of 12:1, where the bottom
wall of the test section consists of a train of sinusoidal waves. The wavy wall is characterized by the amplitude to wavelength
ratio α = 0.05 and the ratio β between the wave amplitude and the half channel height where β = 0.1. The scalar is released
from a point source at the wave crest. For the concentration measurements, Rhodamine B is used as tracer dye. At low to moderate
Reynolds number, the flow field is characterized through a recirculation zone which develops after the wave crest. The recirculation
zone induces high intensities of the fluctuations of the streamwise velocity and wall-normal velocity. Furthermore, large-scale
structures are apparent in the flow field. In previous investigations it has been shown that these large-scale structures
meander laterally in flows over wavy bottom walls. The investigations show a strong effect of the wavy bottom wall on the
scalar mixing. In the vicinity of the source, the scalar is transported by packets of fluid with a high scalar concentration.
As they move downstream, these packets disintegrate into filament-like structures which are subject to strong gradients between
the filaments and the surrounding fluid. The lateral scale of the turbulent plume is smaller than the lateral scale of the
large-scale structures in the flow field and the plume dispersion is dominated by the structures in the flow field. Due to
the lateral meandering of the large-scale structures of the flow field, also the scalar plume meanders laterally. Compared
to turbulent plumes in plane channel flows, the wavy bottom wall enhances the mixing effect of the turbulent flow and the
spreading rate of the scalar plume is increased. 相似文献
3.
Topological aspects of the turbulent wake of a finite, surface-mounted, square-cross-section cylinder of h/d = 4 are addressed by decomposing the velocity field into a quasi-periodic coherent part and the unresolved incoherent fluctuations. The three-dimensional large scale structure is educed through a reconstruction of planar phase-averaged PIV measurements using the simultaneously sampled surface pressure difference on opposing sides of the obstacle as a phase reference. A topological model for the vortex structure is educed and mean streamwise wake vorticity is explained in terms of the connections between initially vertical structures shed alternately from either side of the obstacle, rather than previously proposed ‘tip’ vortex structures generated at the obstacle free-end. The coherent structure educed accounts for a significant portion of the fluctuating energy in the wake. The turbulent field is further analyzed by finding Lagrangian straining structures that form by induction of the coherent vorticity field, and these structures are related to the energy transfer from the base phase-averaged flow since they act to stretch incoherent vorticity fluctuations in their neighbourhood. 相似文献
4.
K. Suga Y. Matsumura Y. Ashitaka S. Tominaga M. Kaneda 《International Journal of Heat and Fluid Flow》2010,31(6):974-984
In order to understand the effects of the wall permeability on turbulence near a porous wall, flow field measurements are carried out for turbulent flows in a channel with a porous bottom wall by a two-component particle image velocimetry (PIV) system. The porous media used are three kinds of foamed ceramics which have almost the same porosity (0.8) but different permeability. It is confirmed that the flow becomes more turbulent over the porous wall and tends to be turbulent even at the bulk Reynolds number of Reb=1300 in the most permeable wall case tested. Corresponding to laminar to turbulent transition, the magnitude of the slip velocity on the porous wall is found to increase drastically in a narrow range of the Reynolds number. To discuss the effects of the wall roughness and the wall permeability, detailed discussions are made of zero-plane displacement and equivalent wall roughness for porous media. The results clearly indicate that the turbulence is induced by not only the wall roughness but the wall permeability. The measurements have also revealed that as Reb or the wall permeability increases, the wall normal fluctuating velocity near the porous wall is enhanced due to the effects of the wall permeability. This leads to the increase of the turbulent shear stress resulting in higher friction factors of turbulence over porous walls. 相似文献
5.
Three-dimensional LDA measurements in the impeller region of a turbulently stirred tank 总被引:1,自引:0,他引:1
Three-dimensional, angle-resolved LDA measurements of the turbulent flow field (Re = 2.9 × 104) in the vicinity of a Rushton turbine in a baffled mixing tank have been performed. For this goal, a procedure for accurate
beam alignment, based on a submerged micro-mirror system, has been developed. Results on the average flow field as well as
on the complete set of Reynolds stresses are presented. The anisotropy of the turbulence has been characterized by the invariants
of the anisotropy tensor. The trailing vortex structure, which is characteristic for the flow induced by a Rushton turbine,
is demonstrated to be associated with strong, anisotropic turbulent activity.
Received: 14 September 1998/Accepted: 22 February 1999 相似文献
6.
Large-eddy simulations (LES) of a planar, asymmetric diffuser flow have been performed. The diverging angle of the inclined
wall of the diffuser is chosen as 8.5°, a case for which recent experimental data are available. Reasonable agreement between
the LES and the experiments is obtained. The numerical method is further validated for diffuser flow with the diffuser wall
inclined at a diverging angle of 10°, which has served as a test case for a number of experimental as well as numerical studies
in the literature (LES, RANS). For the present results, the subgrid-scale stresses have been closed using the dynamic Smagorinsky
model. A resolution study has been performed, highlighting the disparity of the relevant temporal and spatial scales and thus
the sensitivity of the simulation results to the specific numerical grids used. The effect of different Reynolds numbers of
the inflowing, fully turbulent channel flow has been studied, in particular, Re
b
= 4,500, Re
b
= 9,000 and Re
b
= 20,000 with Re
b
being the Reynolds number based on the bulk velocity and channel half width. The results consistently show that by increasing
the Reynolds number a clear trend towards a larger separated region is evident; at least for the studied, comparably low Reynolds-number
regime. It is further shown that the small separated region occurring at the diffuser throat shows the opposite behaviour
as the main separation region, i.e. the flow is separating less with higher Re
b
. Moreover, the influence of the Reynolds number on the internal layer occurring at the non-inclined wall described in a recent
study has also been assessed. It can be concluded that this region close to the upper, straight wall, is more distinct for
larger Re
b
. Additionally, the influence of temporal correlations arising from the commonly used periodic turbulent channel flow as inflow
condition (similar to a precursor simulation) for the diffuser is assessed. 相似文献
7.
A. V. Chebotnikov 《Journal of Applied Mechanics and Technical Physics》2012,53(6):846-853
The results of experiments in which a circular cylinder located near the bottom of a rectangular channel was exposed to transverse statistically stationary turbulent subcritical flow with free surface are presented. The particle image velocimetry (PIV) was used to obtain data on the averaged velocity field near the cylinder. The gradients of the longitudinal velocity component were used to determine the shear stresses on the bottom of the channel. It is shown that the presence of the cylinder in the flow causes considerable averaged vertical velocities and a significant change in the shear stresses on the bottom of the channel. 相似文献
8.
The paper describes the validation of a newly developed very LES (VLES) method for the simulation of turbulent separated flow. The new VLES method is a unified simulation approach that can change seamlessly from Reynolds‐averaged Navier–Stokes to DNS depending on the numerical resolution. Four complex test cases are selected to validate the performance of the new method, that is, the flow past a square cylinder at Re = 3000 confined in a channel (with a blockage ratio of 20%), the turbulent flow over a circular cylinder at Re = 3900 as well as Re = 140,000, and a turbulent backward‐facing step flow with a thick incoming boundary layer at Re = 40,000. The simulation results are compared with available experimental, LES, and detached eddy simulation‐type results. The new VLES model performs well overall, and the predictions are satisfactory compared with previous experimental and numerical results. It is observed that the new VLES method is quite efficient for the turbulent flow simulations; that is, good predictions can be obtained using a quite coarse mesh compared with the previous LES method. Discussions of the implementation of the present VLES modeling are also conducted on the basis of the simulations of turbulent channel flow up to high Reynolds number of Reτ = 4000. The efficiency of the present VLES modeling is also observed in the channel flow simulation. From a practical point of view, this new method has considerable potential for more complex turbulent flow simulations at relative high Reynolds numbers. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
9.
Jan G. Wissink 《国际流体数值方法杂志》1997,25(1):51-62
Two-dimensional ‘turbulent’ flow around a rectangular cylinder has been simulated at Re=10,000 using a sixth- order-accurate finite volume method for the discretization of convection and diffusion. The spatial discretization consists of a combination of a seventh- order upwind-biased method for the convective terms and an eighth-order central method for the diffusive terms, discretized on a stretched and staggered grid. To cope with the stretching of the grid, Lagrange interpolations are used. The method applied to obtain a boundary condition for the velocity in the x-direction at the outflow boundary is shown not to affect the flow in the interior of the computational domain in a way that is visible in various snapshots of the vorticity field. The variation in the velocity in the x-direction with time is itself found to be relatively small near the outflow boundary. Several turbulence statistics have been gathered from a simulation of the flow developed during 77 dimensionless time units. Snapshots of the vorticity field of the developed flow show the presence of a vortex-street- like structure. Typical 2D turbulent behaviour, such as the appearance of monopolar, dipolar and tripolar vortices due to the amalgamation of vorticity in the wake and the x−1/2 scaling of the velocity defect in the wake, has been obtained. © 1997 John Wiley & Sons, Ltd. 相似文献
10.
The change in flow characteristics downstream of a circular cylinder (inner cylinder) surrounded by an outer permeable cylinder was investigated in shallow water using particle image velocimetry technique. The diameter of the inner cylinder and the water height were kept constant during the experiments as d?=?50?mm and h w ?=?25?mm, respectively. The depth-averaged free-stream velocity was also kept constant as U?=?170?mm/s which corresponded to a Reynolds number of Red?=?8,500 based on the inner cylinder diameter. In order to examine the effect of diameter and porosity of the outer cylinder on flow characteristics of the inner cylinder, five different outer cylinder diameters (D?=?60, 70, 80, 90 and 100?mm) and four different porosities (???=?0.4, 0.5, 0.6 and 0.7) were used. It was shown that both porosity and outer cylinder diameter had a substantial effect on the flow characteristics downstream of the circular cylinder. Turbulent statistics clearly demonstrated that in comparison with the bare cylinder (natural case), turbulent kinetic energy and Reynolds stresses decreased remarkably when an outer cylinder was placed around the inner cylinder. Thereby, the interaction of shear layers of the inner cylinder has been successfully prevented by the presence of outer cylinder. It was suggested by referring to the results that the outer cylinder having 1.6????D/d????2.0 and 0.4????D/d????0.6 should be preferred to have a better flow control in the near wake since the peak magnitude of turbulent kinetic energy was considerably low in comparison with the natural case and it was nearly constant for these mentioned porosities ??, and outer cylinder to inner cylinder diameter ratios D/d. 相似文献
11.
This paper reports an experimental study of turbulent momentum and heat transport in the wake of a wall-mounted finite-length
square cylinder, with its length-to-width ratio L/d = 3–7. The cylinder was slightly heated so that heat produced could be considered as a passive scalar. A moveable three-wire
probe (a combination of an X-wire and a cold wire) was used to measure velocity and temperature fluctuations at a Reynolds
number of 7,300 based on d and the free-stream velocity. Measurements were performed at 10 and 20d downstream of the cylinder at various spanwise locations. Results indicate that L/d has a pronounced effect on Reynolds stresses, temperature variance and heat fluxes. The downwash flow from the free end of
the cylinder acts to suppress spanwise vortices and, along with the upwash flow from the cylinder base, makes the finite-length
cylinder wake highly three-dimensional. Reynolds stresses, especially the lateral normal stress, are significantly reduced
as a result of suppressed spanwise vortices at a small L/d. The downwash flow acts to separate the two rows of spanwise vortices further apart from the wake centerline, resulting in
a twin-peak distribution in temperature variance. While the downwash flow entrains high-speed fluid into the wake, responsible
for a small deficit in the time-averaged streamwise velocity near the free end, it does not alter appreciably the distribution
of time-averaged temperature. It has been found that the downwash flow gives rise to a counter-gradient transport of momentum
about the central region of the wake near the free end of the cylinder, though such a counter-gradient transport does not
occur for heat transport. 相似文献
12.
A thre-dimensional direct numerical simulation is combined with a laboratory study to describe the turbulent flow in an enclosed
annular rotor-stator cavity characterized by a large aspect ratio G = (b − a)/h = 18.32 and a small radius ratio a/b = 0.152, where a and b are the inner and outer radii of the rotating disk and h is the interdisk spacing. The rotation rate Ω considered is equivalent to the rotational Reynolds number Re = Ωb
2/ν= 9 .5 × 104 (ν the kinematic viscosity of water). This corresponds to a value at which experiment has revealed that the stator boundary
layer is turbulent, whereas the rotor boundary layer is still laminar. Comparisons of the computed solution with velocity
measurements have given good agreement for the mean and turbulent fields. The results enhance evidence of weak turbulence
by comparing the turbulence properties with available data in the literature (Lygren and Andersson, J Fluid Mech 426:297–326,
2001). An approximately self-similar boundary layer behavior is observed along the stator. The wall-normal variations of the structural
parameter and of characteristic angles confirm that this boundary layer is three-dimensional. A quadrant analysis (Kang et
al., Phys Fluids 10:2315–2322, 1998) of conditionally averaged velocities shows that the asymmetries obtained are dominated by Reynolds stress-producing events
in the stator boundary layer. Moreover, Case 1 vortices (with a positive wall induced velocity) are found to be the major
source of generation of special strong events, in agreement with the conclusions of Lygren and Andersson (J Fluid Mech 426:297–326,
2001). 相似文献
13.
Hot-wire measurements have been carried out in the turbulent flow around a rotating circular cylinder in still air for Reynolds
numbers Re=∣U
w
∣D/ν=1.5×104 to 105. The experimental results confirm the analysis derived by asymptotic theory for high Reynolds numbers. Two different ways
of deriving the friction law from the experiments (via shear stress and via velocity distribution) resulted practically in
the same law. It is shown, that in spite of the curvature of the streamlines the universal logarithmic velocity distribution
is still valid near the wall.
Received: 8 August 1996/Accepted: 24 April 1998 相似文献
14.
Jorge Bailon-Cuba Stefano Leonardi Luciano Castillo 《International Journal of Heat and Fluid Flow》2009,30(5):1007-1015
Direct numerical simulations (DNS) of a turbulent channel flow with 2D wedges of random height on the bottom wall have been performed. In addition, two other simulations have been carried out to assess the effect of the geometry on the overlying flow. In the first simulation, the four smallest elements were removed while in the other, a uniform distribution of wedges with the same area was used. Two Reynolds numbers were studied, Reb=2500 and Reb=5000 which correspond in case of smooth walls to Reτ=180 and 300, respectively. Roughness on the wall induces separated regions, the reattachment occurring on the walls of the wedges or on the bottom wall. The pressure gradients on the walls increase the ejections and inrushes towards the wall. As a consequence the flow is more isotropic. The mechanism inducing an improved isotropy has been explained in term of the spectra and budgets of Reynolds stress. The comparison of the 3 surfaces has shown that near the wall, the uniformly distributed roughness represents only a poor approximation of the surface with wedges of random height. The Reynolds stresses, pressure distribution and spectra on the modified wall agree well with those on the random surface. Energy spectra show the pitch to height ratio of the largest elements to be the more appropriate geometrical parameter to describe the geometry. 相似文献
15.
Augmentation of heat transfer from a flat plate using a turbulence promoter has been studied. A circular cylinder 8 mm in diameter was placed in the turbulent boundary layer detached from the flat plate. It was located parallel to the plate and perpendicular to the flow direction. Clearance, c, between the cylinder and the flat plate was varied in nine steps: c=0, 1, 2, 3, 4, 6, 11, 20 and 29.5 mm. Measurements were made of the local heat transfer coefficients, mean velocity profiles, turbulence intensity profiles, static pressure and skin friction. Experimental results showed that the heat transfer deterioration which occurs just downstream of the cylinder at c=0 mm can be removed by displacing the cylinder a small distance from the wall. The improvement in heat transfer is mainly due to the unsteadiness of the recirculating flow on the plate and the effect of intense turbulence arriving at the near wall region from the lower shear layer of the cylinder wake. Heat transfer augmentation is most effective when c=4 mm and becomes less effective when c is increased more than 6 mm. The enhancement disappears far downstream from the cylinder. 相似文献
16.
Johan Malm Philipp Schlatter Neil D. Sandham 《Theoretical and Computational Fluid Dynamics》2012,26(6):485-499
Vorticity stretching in wall-bounded turbulent and transitional flows has been investigated by means of a new diagnostic measure, denoted by Γ, designed to pick up regions with large amounts of vorticity stretching. It is based on the maximum vorticity stretching component in every spatial point, thus yielding a three-dimensional scalar field. The measure was applied in four different flows with increasing complexity: (a) the near-wall cycle in an asymptotic suction boundary layer (ASBL), (b) K-type transition in a plane channel flow, (c) fully turbulent channel flow at Re τ = 180 and (d) a complex turbulent three-dimensional separated flow. Instantaneous data show that the coherent structures associated with intense vorticity stretching in all four cases have the shape of flat ‘pancake’ structures in the vicinity of high-speed streaks, here denoted ‘h-type’ events. The other event found is of ‘l-type’, present on top of an unstable low-speed streak. These events (l-type) are further thought to be associated with the exponential growth of streamwise vorticity in the turbulent near-wall cycle. It was found that the largest occurrence of vorticity stretching in the fully turbulent wall-bounded flows is present at a wall-normal distance of y +?=?6.5, i.e. in the transition between the viscous sublayer and buffer layer. The associated structures have a streamwise length of ~200–300 wall units. In K-type transition, the Γ-measure accurately locates the regions of interest, in particular the formation of high-speed streaks near the wall (h-type) and the appearance of the hairpin vortex (l-type). In the turbulent separated flow, the structures containing large amounts of vorticity stretching increase in size and magnitude in the shear layer upstream of the separation bubble but vanish in the backflow region itself. Overall, the measure proved to be useful in showing growing instabilities before they develop into structures, highlighting the mechanisms creating high shear region on a wall and showing turbulence creation associated with instantaneous separations. 相似文献
17.
Y.F. Yao T.G. Thomas N.D. Sandham J.J.R. Williams 《Theoretical and Computational Fluid Dynamics》2001,14(5):337-358
This paper describes a direct numerical simulation (DNS) study of turbulent flow over a rectangular trailing edge at a Reynolds
number of 1000, based on the freestream quantities and the trailing edge thickness h; the incoming boundary layer displacement thickness δ* is approximately equal to h. The time-dependent inflow boundary condition is provided by a separate turbulent boundary layer simulation which is in good
agreement with existing computational and experimental data. The turbulent trailing edge flow simulation is carried out using
a parallel multi-block code based on finite difference methods and using a multi-grid Poisson solver. The turbulent flow in
the near-wake region of the trailing edge has been studied first for the effects of domain size and grid resolution. Then
two simulations with a total of 256 × 512 × 64 (∼ 8.4×106) and 512 × 1024 × 128 (∼ 6.7×107) grid points in the computational domain are carried out to investigate the key flow features. Visualization of the instantaneous
flow field is used to investigate the complex fluid dynamics taking place in the near-wake region; of particular importance
is the interaction between the large-scale spanwise, or Kármán, vortices and the small-scale quasi-streamwise vortices contained
within the inflow boundary layer. Comparisons of turbulence statistics including the mean flow quantities are presented, as
well as the pressure distributions over the trailing edge. A spectral analysis applied to the force coefficient in the wall
normal direction shows that the main shedding frequency is characterized by a Strouhal number based on h of approximately 0.118. Finally, the turbulence kinetic energy budget is analysed.
Received 4 March 1999 and accepted 27 October 2000 相似文献
18.
The adverse pressure gradient induced by a surface-mounted obstacle in a turbulent boundary layer causes the approaching flow
to separate and form a dynamically rich horseshoe vortex system (HSV) in the junction of the obstacle with the wall. The Reynolds
number of the flow (Re) is one of the important parameters that control the rich coherent dynamics of the vortex, which are known to give rise to
low-frequency, bimodal fluctuations of the velocity field (Devenport and Simpson, J Fluid Mech 210:23–55, 1990; Paik et al., Phys Fluids 19:045107, 2007). We carry out detached eddy simulations (DES) of the flow past a circular cylinder mounted on a rectangular channel for
Re = 2.0 × 104 and 3.9 × 104 (Dargahi, Exp Fluids 8:1–12, 1989) in order to systematically investigate the effect of the Reynolds number on the HSV dynamics. The computed results are compared
with each other and with previous experimental and computational results for a related junction flow at a much higher Reynolds
number (Re = 1.15 × 105) (Devenport and Simpson, J Fluid Mech 210:23–55, 1990; Paik et al., Phys Fluids 19:045107, 2007). The computed results reveal significant variations with Re in terms of the mean-flow quantities, turbulence statistics, and the coherent dynamics of the turbulent HSV. For Re = 2.0 × 104 the HSV system consists of a large number of necklace-type vortices that are shed periodically at higher frequencies than
those observed in the Re = 3.9 × 104 case. For this latter case the number of large-scale vortical structures that comprise the instantaneous HSV system is reduced
significantly and the flow dynamics becomes quasi-periodic. For both cases, we show that the instantaneous flowfields are
dominated by eruptions of wall-generated vorticity associated with the growth of hairpin vortices that wrap around and disorganize
the primary HSV system. The intensity and frequency of these eruptions, however, appears to diminish rapidly with decreasing
Re. In the high Re case the HSV system consists of a single, highly energetic, large-scale necklace vortex that is aperiodically disorganized
by the growth of the hairpin mode. Regardless of the Re, we find pockets in the junction region within which the histograms of velocity fluctuations are bimodal as has also been
observed in several previous experimental studies. 相似文献
19.
We describe how outer flow turbulence phenomena depend on the interaction with the wall. We investigate coherent structures
in turbulent flows over different wavy surfaces and specify the influence of the different surface geometries on the coherent
structures. The most important contribution to the turbulent momentum transport is attributed to these structures, therefore
this flow configuration is of large engineering interest. In order to achieve a homogeneous and inhomogeneous reference flow
situation two different types of surface geometries are considered: (1) three sinusoidal bottom wall profiles with different
amplitude-to-wavelength ratios of α = 2a/Λ = 0.2 (Λ = 30 mm), α = 0.2 (Λ = 15 mm), and α = 0.1 (Λ = 30 mm); and (2) a profile consisting of two superimposed sinusoidal
waves with α = 0.1 (Λ = 30 mm). Measurements are carried out in a wide water channel facility (aspect ratio 12:1). Digital
particle image velocimetry (PIV) is performed to examine the spatial variation of the streamwise, spanwise and wall-normal
velocity components in three measurement planes. Measurements are performed at a Reynolds number of 11,200, defined with the
half channel height h and the bulk velocity U
B. We apply the method of snapshots and perform a proper orthogonal decomposition (POD) of the streamwise, spanwise, and wall-normal
velocity components to extract the most dominant flow structures. The structure of the most dominant eigenmode is related
to counter-rotating, streamwise-oriented vortices. A qualitative comparison of the eigenfunctions for different sinusoidal
wall profiles shows similar structures and comparable characteristic spanwise scales Λ
z
= 1.5 H in the spanwise direction for each mode. The scale is observed to be slightly smaller for α = 0.2 (Λ = 15 mm) and slightly
larger for α = 0.2 (Λ = 30 mm). This scaling for the flow over the basic wave geometries indicates that the size of the largest
structures is neither directly linked to the solid wave amplitude, nor to the wavelength. The characteristic spanwise scale
of the dominant eigenmode for the developed flow over the surface consisting of two superimposed waves reduces to 0.85 H. However, a scale in the order of 1.3 H is identified for the second mode. The eigenvalue spectra for the superimposed waves is much broader, more modes contribute
to the energy-containing range. The turbulent flow with increased complexity of the bottom surface is characterized by an
increased number of dominant large-scale structures with different spanwise scales. 相似文献
20.
In this paper a typical fluid-structure interaction scenario is investigated for a turbulent flow past a circular cylinder
at a relatively low subcritical Reynolds number. Numerous experimental and numerical studies have been undertaken for a baseline
Reynolds number of 4,000 involving a stationary cylinder to study in detail the near wake mean flow and turbulence characteristics.
These studies conclusively show that the turbulent wake displays significant coherent periodic structures of large eddies
that could be adequately and profitably resolved by “low order modelling” of turbulence. In this study, an unsteady numerical
framework is employed for the simulations, incorporating an Arbitrary Lagrangian–Eulerian (ALE) method for the associated
grid deformation to simulate the coupled motion of the circular cylinder with a single degree of freedom in the initial zone
in a typical cylinder-flow response map or what is called “initial regime”. Particular attention is paid towards resolving
the large scales of the fluid motion and the inherent coupling of the cylinder’s motion towards the associated evolution of
the time averaged flow field. The flow-induced vibration effects regarding the kinetic energy exchange between the mean flow
and the coherent periodic scales are investigated further. The predictions discussed and analyzed in detail in the paper display
reasonable agreement with the chosen benchmark tests of the stationary cylinder and suggest that the conclusions outlined
regarding the coupled flow-cylinder system potentially provides a valuable contribution to the state of the art. 相似文献