Oscillation Of Cylinder Research Articles

Vortex shedding analysis of flows past forced-oscillation cylinder with dynamic mode decomposition

Direct numerical simulations are performed for flow past circular cylinders by the lattice Boltzmann method coupled with immersed moving boundary method. By analyzing the flows past a single cylinder at a wide range of cross-flow or in-line oscillation amplitude (0.25≤A/D≤1.5) and frequency (0.5≤fe/f0≤1.5), the results find that the vortex shedding modes inside and outside “lock-in” interval are of significant difference. The vortex shedding mode in the “unlock-in” state is 2S, but C(2S) and P + S shedding modes can be found in the lock-in state. Dynamic mode decomposition is used to analyze characteristic flow features, which shows that mode 1 is the main factor reflecting the flow field structure and mode 2 represents the vortex shedding mode in this work. The vortex shedding modes of flows past a tandem and side-by-side cross-flow double oscillating cylinders are systemically investigated. For tandem double oscillation cylinders, the results of modal decomposition suggest that the shear layer of upstream oscillating cylinder is separated behind the downstream cylinder at a space rate of L/D≤2, but separated behind the upstream cylinder at L/D≥3. Mode 2 at L/D=4 differs from other vortex shedding modes due to the strong inhibition effect by the downstream cylinder on the vortex formation of upstream cylinder. For side-by-side double oscillation cylinders, the wake of two cylinders is a single vortex street at H/D=1, a bistable flow at H/D=2 or 3, a coupled vortex street at H/D=4, and close to a single cylinder at H/D>4. The results of modal decomposition are disordered at H/D=2 due to the interaction between two cylinders and effect of gap flow.

Experimental and numerical study of the shielding effect of two tandem rough cylinders in flow-induce oscillation

The shielding effect of the downstream cylinder in flow induced oscillation (FIO) of two cylinders arranged in tandem is studied experimentally and numerically at Reynolds number 30,000 to 120,000. Both cylinders are in one degree-of-freedom, transverse-oscillations, and have turbulence stimulation in the form of selective surface roughness to expand FIO beyond vortex-induced vibration (VIV) into galloping. Shielding of the downstream cylinder has a negative effect on harnessing hydrokinetic energy. To study its effect and mechanics, selective cases are studied both numerically and experimentally and discussed to demonstrate the shielding effect on the downstream cylinder and understand its cause. The main conclusions are: (1) The shielding effect for the downstream cylinder shows a strong relation to the damping ratio. As the damping ratio increases, the shielding effect is mitigated. Additionally, the oscillation of the rear cylinder becomes stable and shows stable frequency. (2) In the VIV region, as the stiffness and natural frequency increase, the shielding effect decreases substantially. (3) In the VIV region, the vorticity of the vortices shedding from both the upper and the lower sides of the downstream cylinder does not accumulate enough due to the attraction by the vortices shed from the upstream cylinder, thus resulting in partial suppression of the oscillation on the downstream cylinder. (4) In the galloping region, the shielding effect for the downstream cylinder depends on whether the vorticity near the downstream cylinder is strengthened by the vortices generated by the shear layers of the upstream cylinder or weakened.

Application of Vortex Induced Vibration Systems to Improve Vertical Mixing and Create Light/Dark Cycles for Enhanced Algal Biomass Productivity in Raceway Ponds

Limited light availability due to insufficient vertical mixing is one of the main drawbacks of raceway ponds (RWPs), the most common type of microalgae cultivation system. In this study, we have investigated the application of vortex induced vibration (VIV) systems to improve vertical mixing in order to enhance algal biomass productivity. The system consists of a cylinder submerged parallel to the bottom in the pond with two springs attached at its ends. The cylinder oscillates perpendicularly to the flow direction at the pond to increase vertical mixing. A VIV system, which requires no additional energy input, was installed in a 0.3 m deep raceway pond and continuous cylinder oscillation was successfully achieved. Cylinder oscillation frequency of 1.24 s−1 and amplitude of 6.5 cm have been obtained experimentally for 0.3 m s−1 flow velocity. Numerical simulations were carried out with experimental parameters using CFD code and were in good accordance with experimental results. Numerical analysis revealed that it is possible to create high frequency light/dark cycles; mean light/dark cycle frequencies were found to be 2.33 s−1, 5.28 s−1 and 21.17 s−1, at lowermost, middle and uppermost cylinder positions, respectively. Enhanced velocity magnitude of 0.3 m s−1 was achieved in the vertical direction; vertical motion of flow resulting from cylinder oscillation covers about two thirds of pond depth. Effectiveness of the VIV system on biomass growth was also verified by comparative Chlorella vulgaris cultivation under outdoor conditions. It has been observed that the VIV system installed reactor enhanced biomass production capacity by over 20% compared to the control pond. These results indicate that the presented method possesses a potential for enhanced algal biomass production without significant increase in installation and operating costs.

Numerical investigation of noise suppression and amplification in forced oscillations of single and tandem cylinders in high Reynolds number turbulent flows

The noise generated by a three-dimensional turbulent wake behind an oscillating single or tandem cylinder(s) is studied using detached eddy simulation and the Ffowcs Williams-Hawkings (FW-H) method. This hybrid methodology is validated using some experimental data of a turbulent flow past a single or tandem stationary cylinder(s) and some numerical data (obtained from a direct numerical simulation) of a laminar flow past tandem oscillating cylinders. For an oscillating cylinder at a fixed Reynolds number Re=120,000, the sound energy is suppressed compared to that of a stationary cylinder provided the value of oscillation frequency approaches 57% of the original vortex-shedding frequency of the stationary cylinder. This noise reduction arises from the structural oscillations suppressing the noise generated by the vortex shedding from the stationary cylinder—the additional source of noise stemming from the structural oscillations is too small to compensate for the mechanism responsible for the noise suppression. The noise generated by the cylinder motion includes contributions from the loading and thickness noise, whereas the noise generated by vortex shedding from the stationary cylinder only includes the loading noise. The flow past tandem stationary cylinders exhibits a larger number of spectral peaks in the sound pressure power spectrum and the peaks occur at a lower frequency compared to the flow past a single cylinder. The drag force fluctuations result in the propagation of the sound pressure in the in-line direction, whereas the lift force fluctuations result in the propagation of the sound pressure in the transverse direction. Five different scenarios of stationary and/or oscillating tandem cylinders are studied. The second and third invariants of the velocity gradient tensor are used to visualize the distinct vortex structures in the wake for the five different scenarios of tandem cylinders. A single cylinder oscillating in the transverse direction exhibits a larger sound pressure level (SPL) than the streamwise oscillation of the same cylinder. In contrast, the streamwise (in-line) oscillation of one or the other cylinder in a tandem array results in a larger SPL than the transverse oscillation of one or the other cylinder. Finally, the SPL is more sensitive to the oscillations of the rear (downstream) cylinder than the front (upstream) cylinder.

Mixed convection of a non-Newtonian fluid in a square enclosure with rotating and oscillating cylinder

Two-dimensional simulations of laminar mixed convection in a square enclosure subjected to constant wall temperature with a heated rotating and oscillating cylinder have been carried out. The enclosure is filled with non-Newtonian fluid. Due to the rotation and oscillation of the cylinder, forced convection effects are set up along with the natural convection. Observations are made on the dynamic behavior of the flow features and temperature fields due to the rotation and oscillation of hot cylinder inside a square enclosure. The comparison between the rotating and oscillating cylinder on heat transmission has also been made. Overall, the present study focuses on how the rotating and oscillating cylinder affects the thermo-fluid behavior of non-Newtonian fluids and quantifies heat transfer characteristics.

Investigation of the Influence of Cylinder's Oscillation Amplitude on the Lock-in Range of an In-line Oscillating Circular Cylinder

Investigation of the Influence of Cylinder's Oscillation Amplitude on the Lock-in Range of an In-line Oscillating Circular Cylinder

The influence of reduced velocity on the control of two-degree-of-freedom vortex induced vibrations of a circular cylinder via synthetic jets

A two-dimensional numerical study is conducted to investigate the influence of the reduced velocity on two-degree-of-freedom vortex induced vibrations of a circular cylinder controlled by synthetic jets ejected in horizontal and vertical directions (β = 0° and β = 90°). The Reynolds number is constant at Re = 150, and the reduced velocity varies in the range of 2.5 and 15 (U* = 2.5–15). The mass ratio of the circular cylinder is 2.0, and the in-flow to the cross-flow natural frequency ratio equals 1.0 (f nx /f ny = 1.0). The oscillation characters, hydrodynamic forces and vortex shedding of circular cylinders with or without synthetic jets control are analyzed and compared. The results indicate that synthetic jets ejected in vertical direction (β = 90°) can intensify both in-flow and cross-flow oscillations of the circular cylinder in the whole reduced velocity range, the vortex shedding of the controlled case (β = 90°) becomes complicated even unstable with the reduced velocity increasing. Synthetic jets ejected in horizontal direction (β = 0°) have excellent performance on suppressing the cross-flow oscillation of the circular cylinder in the whole reduced velocity range. When U* ⩾ 8.0, the in-flow oscillation of the circular cylinder can even be intensified by synthetic jets ejected in horizontal direction (β = 0°).

Effect of three tandem cylinder diameter difference on flow-induced vibrations and heat transfer

The effect of diameter differences of three tandem cylinders on flow-induced vibrations (FIVs) and convection heat transfer characteristics is investigated. The diameter reduction ratios are 0, 0.2, and 0.4, and the cylinder gap ratios are 2 and 4. The simulation is performed at Reynolds number 100, Prandtl number 0.7, reduced velocity 2 - 20, and mass ratio 2. The effect of the diameter reduction ratio on FIVs and heat transfer characteristics is observed through flow structures, oscillation amplitude, shedding frequency, correlation between lift coefficient and cylinder displacement, and Nusselt number. The flow around the downstream cylinder and the associated heat transfer depend strongly on the diameter reduction ratio. The FIV of the downstream cylinder is reduced with the increase in diameter reduction ratio. Indeed, for diameter reduction ratio 0.4 and gap ratio 2, the maximum oscillation amplitude is reduced by 48%. This is because the unequal diameter results in a weaker correlation between lift force and oscillation, modulated oscillation of cylinder, and distribution of primary shedding frequency energy to secondary frequency. At the initial and upper branches of vibration, the heat transfer from the downstream cylinder is enhanced with an increase in diameter reduction ratio due to more exposure to flow and the impingement of the gap vortices. The present flow configuration unveils reduced FIV and enhanced heat transfer, which is a desirable characteristic of multiple heated tubes for structural durability and better performance.

Flow-induced vibration on two tandem cylinders of different diameters and spacing ratios

This work numerically investigates flow-induced vibration (FIV) of two tandem cylinders of unequal diameters at a Reynolds number of 100 and at a range of reduced velocity 2 − 10. Particular attention is paid to assimilating the effects of the cylinder diameter ratio (0.2 − 1) and the cylinder spacing ratio 1.5, 3.5 and 5.5 on vibration responses, frequency responses, lock-in, and wake structure. The cylinder-to-fluid mass ratio is considered as one, and the damping coefficient is set to zero to attain maximum oscillation amplitude. The obtained results reveal that FIV is highly sensitive to both diameter and spacing ratios, and the wake interference involved is intricate. With a decrease in diameter ratio, the upstream cylinder oscillation is affected due to a change in its effective Reynolds number while its wake induces a significant effect on the downstream cylinder. The lowest diameter ratio of 0.2 exhibits a de-energized wake suppressing the oscillation of the downstream cylinder. At a moderate diameter ratio of 0.6, suppressed and excited oscillations of the downstream cylinder are observed at spacing ratios 1.5 and 3.5, respectively.

Active vibration control of tandem square cylinders for three different phenomena: Vortex-induced vibration, galloping, and wake-induced vibration

When exposed to fluid flow, elastically supported multiple square cylinders may experience either one or a combination of vortex-induced vibration, galloping, and wake-induced vibration phenomena. Due to these high-amplitude instabilities, it is necessary to utilize vibration control devices. The present paper studies the suppression of flow-induced vibration (FIV) of tandem-arranged square-section cylinders, which can oscillate independently in the streamwise and transverse directions at low Reynolds numbers. The vibration reduction is achieved by directly applying opposing forces using an active FIV control system based on the intelligent proportional-integral-derivative controller. In the present study, the fluid flow equations are calculated through the finite volume technique, by which the aerodynamic forces are attained. Next, based on the computed excitation forces, the motion equations of cylinders are solved within a user-defined function code. The numerical results show that the controller successfully suppresses the vibrations of the front and rear cylinders by a maximum of 94% and 92% at Re = 80 and by 98% and 97% at Re = 100. At Re = 230 and 250, the controller successfully diminishes the oscillation of the front cylinder by a maximum of 79% and 80%, respectively. The significant intensity of the front cylinder's wake makes the active control system unable to capably affect the vibrations of the downstream cylinder at Re = 230 and 250.

Heat Transfer Past a Rotationally Oscillating Circular Cylinder in Linear Shear Flow

Abstract This study investigates the unsteady, two-dimensional flow and heat transfer past a rotationally oscillating circular cylinder in linear shear flow. A higher order compact (HOC) finite difference scheme is used to solve the governing Navier–Stokes equations coupled with the energy equation on a nonuniform grid in polar coordinates. The hydrodynamic and thermal features of the flow are mainly influenced by the shear rate (K), Reynolds number (Re), Prandtl number (Pr), and the cylinder oscillation parameters, i.e., oscillation amplitude (αm), the frequency ratio (fr). The simulations are performed for Re=100,Pr=0.5−1.0, 0.0≤K≤0.15, and 0.5≤αm≤2.0. The numerical scheme is validated with the existing literature studies. Partial and full vortex suppression is observed for certain values of shear parameter K. The connection between heat transfer and vortex shedding phenomenon is examined where a pronounced increase in the heat transfer is observed for certain values of oscillation parameter, relative to the nonshear flow case.

Reversing and non-reversing Taylor vortex flows in modulated Taylor–Couette flow with counter-oscillating cylinders

Two classes of time-periodic Taylor vortex flows, called reversing and non-reversing flows, were discovered by Youd et al. (2003) under the effect of a zero mean inner cylinder’s angular velocity modulation with fixed outer cylinder. In the non-reversing/reversing flow, which takes place at relatively high/low frequency, the direction of the Taylor vortices in the radial axial-plane is conserved/ not conserved and does not change/change every half-cycle/cycle. This dynamic has been explained on the basis of the time period (frequency) provided by the driving force whether it is sufficiently enough for such flow reversal to be produced. In this paper, we show, using Floquet theory, that the counter-oscillation of the outer cylinder leads to a non-reversing flow suppression in some frequency ranges. In this case, this latter type of Taylor vortex flow could occur only in the very high frequency limit. Taking into account existing results concerning the case of co-oscillating cylinders, it is concluded that the mechanism governing the apparition of such flow reversal in the system does not depends solely to the oscillation frequency but strongly depends on the oscillation of the outer cylinder also.On the other hand, the reported numerical stability diagrams related to this flow configuration (counter-oscillating cylinders) reproduce quite well the existing experimental findings carried-out by Tennakoon et al. (1997). Explanation of discontinuities and jumps pointed-out by these authors in their numerical and experimental stability diagrams is also presented in the framework of the present investigation where we show that these phenomena are due to a switch in the instability of the system between the reversing and non-reversing flows.

Natural convection in a rectangular tall cavity in the presence of an oscillating and rotating cylinder

In this paper, the natural convection in a rectangular tall cavity with a rotating and oscillating cylinder is investigated. The amount of heat transfer due to natural convection for the cavity without a cylinder has been compared with previous references, which is in good agreement with previous results. The effect of changing the width of the cavity (1–7 L), cylinder radius (0.05–0.25 L), angular velocity (−7.5 to 7.5 rad/s), coordinates of the cylinder in the horizontal direction of the hot wall (0.15D-0.85D) and the coordinates of the center of the cylinder in the vertical direction (−0.3D to 0.5D) on the heat transfer has been studied. Cylinder oscillations in the y- direction is assumed sinusoidal. The obtained results revealed that the radius of the cylinder and the distance of the cylinder from the hot wall are two factors affecting the heat transfer and the optimal state was found for them in which the heat transfer is maximum. Also, the rotation and vertical movement of the cylinder has improved heat transfer compared to the static cylinder. With increasing rotational speed, amplitude and frequency of oscillations, the amount of heat transfer increases. In the case where the rotation of the cylinder is clockwise, the Heat transfer is more significant than in the case of counterclockwise rotation. Using a porous cylinder on the heat transfer rate has been investigated. The use of porous cylinders in this case improves heat transfer and by increasing the porosity coefficient in the porous media, the amount of heat transfer is enhanced by about 13%.

Three-dimensional direct numerical simulations of two interfering side-by-side circular cylinders at intermediate spacing ratios

Side-by-side arranged circular cylinders show fierce interferences when they are not far apart. In this paper, we present the vibration response and wake characteristics of two elastically mounted circular cylinders in a side-by-side arrangement through three-dimensional direct numerical simulations (3-D DNS). The Reynolds number is Re = 500 and two center-to-center spacings (s) of 2.0D and 2.5D are considered where D is the diameter of the two cylinders. We found that with the increasing reduced velocity, the responses of both s/D cases can be divided into three different regions, which are named desynchronization region (DS), initial branch (IB), and lower branch (LB), with the former being further divided into two subregions (DS-I and DS-II). The vibration, hydrodynamic forces, and spectral features in each region are discussed in detail. According to the characteristics of cylinder oscillation and vortex dynamics, six types of wake patterns are identified, with the deflected (DF) and flip-flopping (FF) patterns at s/D = 2.0 while in-phase (IP), anti-phase (AP), in-/anti-phase (I/AP), and hybrid (HB) patterns at both s/D = 2.0 and 2.5. Furthermore, we investigated the wake three-dimensionality through the evolution of vortical structures, and the statistics and development of the enstrophies. It was observed that the presence of the streamwise vortices modifies the strength and spanwise coherence of the spanwise vortices. Finally, flow physics for the interactions of the two cylinders at different regions is elucidated.

Analysis of drag reduction effects in turbulent Taylor–Couette flow controlled via axial oscillation of inner cylinder

Analysis of drag reduction effects due to axial oscillation of an inner cylinder in a turbulent Taylor–Couette (TC) flow is performed in the present study. The frictional Reynolds number on the inner cylinder is 218, and the non-dimensional oscillating period is varied from 8 to 32. By examining turbulence statistics, we uncover different impacts of the long- and short-period oscillations on the circumferential (θ) and radial (r) velocity fluctuations in large (uθl, url) and small (uθs, urs) scales. One of the most surprising findings is that the short-period oscillation increases the large-scale Reynolds shear stress ⟨uθlurl⟩ by the strong intensification of uθl exceeding the suppression of url. To understand the phenomena, the spectra of each term in the transport equations of the Reynolds normal stresses ⟨uθ′uθ′⟩ and ⟨ur′ur′⟩ are analyzed. First, it is shown that the short-period oscillation weakens the productions of uθs, urs, and url while it enhances that of uθl. In contrast, the long-period oscillation reduces the productions of uθl and url while it mainly intensifies that of urs. Second, the investigations of the pressure–strain terms indicate that the short-period oscillation mainly impedes the inter-component energy transfer originating from the small-scale background turbulence. However, the long-period oscillation benefits the small-scale inter-component energy communication while it hinders the large-scale one. In addition, the inverse energy transfer in the turbulent TC flow is confirmed by inspecting the inter-scale energy transfer terms. The hindrance of the inter-scale energy transfer by the inner-cylinder oscillation plays a non-negligible role in the reduction of the wall friction drag.

Dynamics and wake structure of a near-wall flexible cylinder

Interactions between the structural dynamics and wake of a vibrating flexible cylinder close to a wall are investigated using three-dimensional direct numerical simulation at reduced velocity Ur = 5-25, gap-to-diameter ratio G/D = 0.8, aspect ratio L/D = 50, and Reynolds number Re = 500. The 1st to 4th cross-flow (CF) vibration modes and the 1st to 9th in-line (IL) vibration modes are excited, and four types of modal groups for the ratio of IL to CF modes are identified, including groups ‘n:n’, ‘2n-1:n’, ‘2n:n’, and ‘2n+1:n’, where n refers to the excited mode in the CF direction. With the increase of Ur, the vibration responses are first dominated by one specific mode and then co-dominated by multi-modes with comparable intensities. Within the same modal group, the maximum CF and IL amplitudes and mean drag/lift coefficients decrease with Ur under smaller Ur conditions, whereas they increase with Ur under larger Ur conditions. The cylinder oscillation exhibits a standing-wave behavior and a mixture of standing and traveling behavior at the lower and higher Ur cases, respectively. Compared to the isolated case, the reduction of the IL vibration frequency by half and the enhanced IL amplitude are caused by the vortex shedding suppression from the lower side of the cylinder and by the corresponding IL lock-in state along the span. The vortex sheddings at the antinode and node of the CF displacement are in ‘2S’ and weak ‘2S ’ modes, with the energy input and output from the wake, respectively; whereas, for the isolated case, they are in ‘2P’ and ‘2S’ modes, respectively.

The effect of a high-speed rotational oscillating cylinder on a heated cylinder

This study investigated the effect of a clockwise and counter-clockwise oscillating (control) cylinder on the flow structure and heat transfer on a heated (bare) cylinder placed in the downstream region of the flow experimentally. In this regard, temperature measurements were made regularly for heat transfer analysis. Particle image velocimetry (PIV) technique was used to determine the instantaneous and time averaged flow characteristics such as streamlines (<ψ > ), turbulent kinetic energy (<TKE > ), vorticity contours (<ω > ), the root mean square of streamwise velocity fluctuations < Urms>, and the root mean square of spanwise velocity fluctuations < Vrms >. The effects of oscillating amplitudes and oscillating speed (forcing frequency) on velocity distributions were also analysed at a specified location. The experiments were conducted at the Reynolds number (Re) 5000 based on the diameter of the bare cylinder with two different oscillating amplitudes 8π and 16π and three different forcing frequencies (FR) 3.5, 7 and 14. With the increase of forcing frequencies, it was observed that the wake region became narrower compared to the main cylinder, and then smaller after being moved towards the cylinder wall. In the case of FR = 3.5-16π, the boundary layer separation was found to be prevented by the effect of the oscillating speed and oscillating amplitude, and the dead zone in the rear of the cylinder was completely eliminated. The heat transfer was found to be evenly distributed at almost all points around the cylinder, and to show the best result especially in the rear of the cylinder among all the cases studied. The results obtained from the temperature and PIV experiments were consistent with each other.

Irregular vortex-induced vibrations of a two-dimensional circular cylinder at a low Reynolds number

Irregular vortex-induced vibrations (VIV) of a two-dimensional circular cylinder, characterized by the time-varying oscillation amplitude and frequency, were observed in both experiments and numerical simulations. This paper attempts to elucidate the phenomena by numerical simulations of a circular cylinder in VIV, with mass ratios of 2, 10 and 50, at a Reynolds number of 150. The lift force acting on the cylinder is assumed to be a sum of two components associated with added mass and hydrodynamic damping. The time-dependent added-mass and hydrodynamic damping coefficients are determined by the least-squares fit of lift from the cylinder displacement. The effective natural frequency varies with time due to the added mass, and the cylinder oscillation amplitudes are influenced by the hydrodynamic damping force. Consequently, VIV irregularities arise from the complex evolution of the added-mass and hydrodynamic damping coefficients. The irregular oscillations are associated with the interaction of vortices in the near wake, which results in the intermittent appearance of disorganized Karman vortex street. Moreover, the vortex interactions involve a rapid reduction of the hydrodynamic damping coefficients. Besides, the irregular oscillation region is identified in terms of the reduced velocity, and smaller mass ratio tends to have larger width of the region.

Nonlinear wave resonance due to oscillations of twin cylinders in a uniform current

A higher order finite element method with 8-node element is adopted to analyse the nonlinear wave resonance generated by oscillations of twin cylinders in a uniform current. The velocity potential in the fluid domain at each time step is obtained based on the finite element method through an iteration procedure. Numerical results are provided for twin rectangular cylinders undergoing specified oscillations in a uniform current at resonant frequencies. The effects of current on the wave and hydrodynamic force at the resonant frequencies are studied in detail and it is found that the resonance happens at all first-order resonant frequencies for both symmetric and antisymmetric motions of the cylinders. In particular, in addition to the first-order resonant frequency, the maximum wave elevation and horizontal force at resonance always regularly increase or decrease as the increase of the absolute value of Froude number or the spacing between two cylinders within the range of larger spacings. A similar trend can be also observed in the oscillational frequency of cylinders at resonance. Some results are also compared with those by linear solution and its superposition with the second-order, their difference at different Froude numbers are also discussed.

Rotational and translational oscillations of cylinders of small aspect ratio in the air flow

Rotational and translational oscillations of three cylinders differing in the ratio of length to cylinder diameter (elongation) are considered. The cylinders were suspended in the test section of the low velocity wind tunnel on a wire suspension containing steel springs. In the equilibrium position, the axis of the cylinders is directed horizontally and parallel to the velocity vector of the incoming flow. Under the influence of the air flow, the cylinders could make rotational or translational oscillations. Semiconductor strain gauges are attached to the two suspension springs, measuring the periodically changing tension of the springs during oscillations. The analog signal from the strain gauges was transmitted to a PC oscilloscope, which transmitted it in digital form to a computer. After calibration of the device and decoding of the signal, the frequencies and amplitudes of translational oscillations in the vertical direction and rotational oscillations around the horizontal axis passing through the center of the cylinder and perpendicular to the velocity vector of the incoming flow were determined. It turned out that in the studied range of cylinder elongations there is a transition from rotational to translational oscillations. A cylinder with elongation 1.9 performs steady rotational oscillations under the influence of wind, the amplitude of which increases with increasing air flow velocity. The previously proposed mathematical model correctly predicts rotational oscillations. The square of the amplitude of rotational oscillations is a linear function of the Strouhal number if the velocity of the air flow is sufficiently large. Translational oscillations of the cylinder with elongation 1.9 are damped. A decrease in the elongation of the cylinder to 1.5 is accompanied by a decrease in the amplitudes of rotational vibrations. At low air flow velocities, translational oscillations with a small amplitude are registered. Further reduction of the elongation to 1.0 leads to the complete absence of rotational oscillations. The amplitude of translational oscillations is growing. Translational oscillations are realized in a limited range of air flow velocities.