Slanted cylinder afterbody aerodynamics measured by 0.3-m magnetic suspension and balance system with six-degrees-of-freedom control

Tashiro, Kodai; Yokota, Sho; Zigunov, Fernando; Ozawa, Yuta; Asai, Keisuke; Nonomura, Taku

doi:10.1007/s00348-022-03470-1

Cited by 9 publications

(6 citation statements)

References 14 publications

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“…The sensor subsystem consists of five charge-coupled device (CCD) line sensors, nine blue light-emitting-diode (LED) light sources, short-pass optical filters, plano-convex lenses and half mirrors. This structure was also adopted in the previous studies (Yokota et al 2021(Yokota et al , 2022(Yokota et al , 2023Tashiro et al 2022). On the other hand, another configuration can be adopted when the fineness ratio is low (Inomata et al 2023;Kuwata et al 2021).…”

Section: Magnetic Suspension and Balance Systemmentioning

confidence: 97%

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Unsteady three-dimensional wake structure behind magnetically levitated freestream-aligned circular cylinder

Yokota

Nonomura

2023

AIAA SCITECH 2023 Forum

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The relationships between characteristic large-scale wake structures appearing behind a freestream-aligned circular cylinder are investigated and discussed from the velocity field obtained by wind tunnel tests. The tests were conducted under a supportless condition using a magnetic suspension and balance system and stereo PIV measurements at a Reynolds number of 3.46 × 10 4 . The velocity fields were analysed with a modal decomposition combining azimuthal Fourier decomposition and proper orthogonal decomposition. Four characteristic large-scale wake structures of recirculation bubble pumping, azimuthal shear, large-scale vortex shedding and streaks are identified and mainly focused on in the present study. The state of the vortex shedding is classified into three; anticlockwise/clockwise circular and flapping patterns. Each state has a relationship with the azimuthal shear and it tends to appear when the state is circular. Furthermore, from the analysis of the relationship between modes, the recirculation bubble pumping is found to be related to the vortex shedding position in the radial direction and the strength of the streaks. Particularly, analysis of causality shows that the recirculation bubble pumping affects them in the low-frequency range.

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Section: Magnetic Suspension and Balance Systemmentioning

confidence: 97%

“…However, problems arise when stings, struts, wires, etc. used as supports interfere with the flow, altering the large-scale wake structure (Tashiro et al 2023). This is known as support interference and makes it difficult to comprehend the actual large-scale wake structure and aerodynamic characteristics that occur in the flow around an object.…”

mentioning

confidence: 99%

Unsteady three-dimensional wake structure behind magnetically levitated freestream-aligned circular cylinder

Yokota

Nonomura

2023

AIAA SCITECH 2023 Forum

View full text Add to dashboard Cite

show abstract

“…The sensor subsystem consists of five charge-coupled device (CCD) line sensors, nine blue light-emitting-diode (LED) light sources, short-pass optical filters, plano-convex lenses and half-mirrors. This structure was also adopted in the previous studies (Yokota et al 2021(Yokota et al , 2022(Yokota et al , 2023Tashiro et al 2022). On the other hand, another configuration can be adopted when the fineness ratio is low (Kuwata et al 2021;Inomata et al 2023).…”

Section: Magnetic Suspension and Balance Systemmentioning

confidence: 99%

“…In most cases of experiments, the model is fixed in the channel by means of support. However, problems arise when stings, struts, wires, etc.used as supports interfere with the flow, altering the large-scale wake structure (Tashiro et al 2023). This is known as support interference and makes it difficult to comprehend the actual large-scale wake structure and aerodynamic characteristics that occur in the flow around an object.…”

Section: Introductionmentioning

confidence: 99%

Unsteady large-scale wake structure behind levitated free-stream-aligned circular cylinder

Yokota,

Nonomura

2024

J. Fluid Mech.

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The relationships between characteristic large-scale wake structures appearing behind a free-stream-aligned circular cylinder are investigated and discussed from the velocity field obtained by wind tunnel tests. The tests were conducted under a supportless condition using a magnetic suspension and balance system and stereo PIV measurements at a Reynolds number of $3.46\times 10^4$ . The velocity fields were analysed with a modal decomposition combining azimuthal Fourier decomposition and proper orthogonal decomposition. The wake behind the free-stream-aligned circular cylinder with three different fineness ratios of 1.0, 1.5 and 2.0 was investigated, and the wake structures in a non-reattaching flow formed by the cylinder at a fineness ratio of 1.0 are mainly discussed in the present study. Four characteristic large-scale wake structures of the recirculation bubble pumping, azimuthal shear mode, large-scale vortex shedding and streaks are identified and mainly focused on in the present study. The state of the vortex shedding is classified into three: anticlockwise/clockwise circular and flapping patterns. Each state has a relationship with the azimuthal shear mode and it tends to appear when the state is circular. Furthermore, from the analysis of the relationship between modes, the recirculation bubble pumping is found to be related to the vortex shedding position in the radial direction and the strength of the streaks. Particularly, analysis of causality shows that the recirculation bubble pumping is affected by them in the low-frequency range.

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“…At present, many countries in the world have carried out research on the engineering application of electromagnetic levitation technology. The research and application fields of maglev technology include medium-and-low-speed maglev transportation system (Hu et al, 2021; Min et al, 2011), high-speed maglev transportation system (Wu et al, 2011), magnetic suspension balance system for wind tunnel (Okuizumi et al, 2021; Tashiro et al, 2022), and various high-speed rotating machinery supported by magnetic bearings (Yan et al, 2019; Liu et al, 2016). With the commercial application of various electromagnetic levitation systems, the electromagnetic levitation control technology (Silva and Barbosa, 2021; Yumuk et al, 2021) has been mature.…”

Section: Introductionmentioning

confidence: 99%

Performance optimization of electromagnetic levitation system based on gradient estimator

Zhou,

Wen,

et al. 2023

Transactions of the Institute of Measurement and Control

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Aiming at the problem of optimal design of the controller of electromagnetic levitation system, this paper proposes a gradient estimator-based controller design and optimization structure suitable for electromagnetic levitation system. The structure consists of a nominal controller, a residual generator, and a dynamic compensator. The controller structure can further improve the anti-disturbance and robustness of the electromagnetic levitation system on the premise of ensuring the stability and reliability. Considering the generality of electromagnetic levitation system, the proportional–integral–derivative (PID) controller is selected as the nominal controller, and the robustness of the system is improved by the dynamic compensator based on the residual generator. The parameter design and update strategy of dynamic compensator based on gradient estimator are proposed, and the expression of gradient estimator is designed and deduced. Taking the single-degree-freedom electromagnetic levitation experimental platform as an example, the simulation and experimental results show that the structure has strong robustness to shock disturbances. Compared with the PID controller, the range of the gap fluctuation is smaller after the instantaneous impact interference, and the anti-interference capability of the electromagnetic levitation system is improved.

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Slanted cylinder afterbody aerodynamics measured by 0.3-m magnetic suspension and balance system with six-degrees-of-freedom control

Cited by 9 publications

References 14 publications

Unsteady three-dimensional wake structure behind magnetically levitated freestream-aligned circular cylinder

Unsteady three-dimensional wake structure behind magnetically levitated freestream-aligned circular cylinder

Unsteady large-scale wake structure behind levitated free-stream-aligned circular cylinder

Performance optimization of electromagnetic levitation system based on gradient estimator

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