Excitation of a Progressive Wave in a Flexurally Vibrating Transmission Medium

Tomikawa, Yoshirô; Adachi, Kazunari; Hirata, Hiroshi; Suzuki, Takanori; Takano, Takehiro

doi:10.7567/jjaps.29s1.179

Cited by 18 publications

(21 citation statements)

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“…In addition, the two-mode excitation method is open-loop controlled and has minimal limitations on the achievable frequencies. However, previous studies have primarily used this method on one-dimensional beams [1,2,33,34]. Traveling waves have been excited on a two-dimensional surface [35], but this was done from a fundamental standpoint and was mainly as a proof of concept.…”

Section: Chapter 1 Introductionmentioning

confidence: 99%

Turbulent Boundary Layer over a Piezoelectrically Excited Traveling Wave Surface

Musgrave

Tarazaga

2019

AIAA Scitech 2019 Forum

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Skin friction drag plays a significant role in determining the fuel efficiency of a vehicle. Reducing the skin friction thus has implications in a number of applications such as aircraft, ships, and automobiles. In recent years, a large amount of studies have researched various active drag reduction methods. One particular method involves active wall motion with the use of spanwise traveling waves. These out-of-plane traveling waves interact with the vortices in the turbulent boundary layer and weaken the bursting events that are responsible for increased skin friction drag. Computational and experimental studies have shown that these spanwise traveling waves are able to reduce the skin friction by upwards of 13% in turbulent flow. However, previous studies generated traveling waves using bulky actuation setups requiring arrays of discrete actuators that limited the achievable bandwidth and traveling wave patterns. In order for traveling waves to be a practical drag reduction method, a more implementable wave generation method is necessary. A promising traveling wave generation method is known as two-mode excitation. This technique takes advantages of a surface's inherent structural properties to generate steady-state traveling waves in an open-loop fashion. In addition, the waves can be excited at most frequencies and using a small number of low-profile piezoelectric actuators. Previous research into two-mode excitation has primarily focused on one-dimensional beams. Traveling waves have been generated on a two-dimensional surface, but this was done from a fundamental standpoint with the resultant waves propagating in arbitrary directions. Before the two-mode excitation method can be applied for drag reduction, traveling waves must be generated on two-dimensional surfaces with tailorable propagation patterns. The goal of this research is the development and testing of an implementable traveling wave generation method that alters the turbulent boundary layer with the aim of reducing skin friction drag. The first objective is to further develop the two-mode excitation method in order to tailor the traveling waves generated on a two-dimensional plate. Then, these tailored traveling waves are experimentally tested to determine their effect on the turbulent boundary layer. By directly investigating the boundary layer, a more fundamental approach is taken than only focusing on the skin friction drag. Finally, the overall effect of the traveling waves on the boundary layer are compared with standing waves. vii None of this would have been possible without the support of my family. My parents, Robert and Jacqueline, you raised me to be the person I am today. You have always been there with support and encouragement, and I am eternally grateful. I want to thank my brothers, Brian and Robert, and their wives, Katie and Lindsay. You are always there to chat and you provided many late nights of fun. Finally, I want to thank Alexis Gushiken and the endless support she has given. You always know when to motivate, encourage, o...

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Section: Chapter 1 Introductionmentioning

confidence: 99%

Turbulent Boundary Layer over a Piezoelectrically Excited Traveling Wave Surface

Musgrave

Tarazaga

2019

AIAA Scitech 2019 Forum

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“…One is through impedance matching using transmission theory [2], [4] and the other is through two-mode excitation [5], in which two neighboring natural mode shapes are excited by forces with the same frequency but a phase difference of 90 • . It is rather difficult to efficiently perform Manuscript the impedance matching in an ultrasonic transmission line because the impedance of the piezoelectric actuator changes with the load and the excitation frequency.…”

Section: Introductionmentioning

confidence: 99%

“…The factors that might affect this speed are weight of the transported object, the excitation frequency, and the phase relationship between excitation forces. In the two-mode excitation method [5], thin patches of piezoeletric material were used to excite the elastic beam. This limits the vibration amplitude of the elastic beam.…”

Section: Introductionmentioning

confidence: 99%

An object transport system using flexural ultrasonic progressive waves generated by two-mode excitation

Loh

2000

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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An object transport system using low amplitude and high frequency progressive waves generated by two-mode excitation is presented. A theoretical model for the system was developed using normal mode expansion and the modal participation factor. To identify the factors that affect the transport speed, the changes with the mass of objects on the beam, the input power, the phase difference, and the excitation frequency were experimentally investigated. With a power input of 40 W, a transport speed of 10 cm/s was obtained for an object weighing 30 g. The tests indicate that, not only the phase difference but also the excitation frequency, were the dominant factors in determining the transport speed and direction. Specifically, when the excitation frequency was chosen to be at the exact midpoint of the two modes, the object stopped moving. A slight change of frequency in either direction resulted in change of object transport direction. For actual factory application, a simple stop-go and tracking control using the General Purpose Interface Bus (GPIB) were implemented.

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“…It has been shown in [3] that at fixed frequency a travelling wave can be obtained with the same modal amplitudes (W A = W B ) shifted by 90…”

Section: Condition For Travelling Wavementioning

confidence: 99%

“…It should be noted that this method requires impedance matching, between the beam and a transducer as described in [2]. The second method [3]- [7] is based on the excitation of two successive flexion modes of the beam, which are excited by forces produced by two transducers. These forces are shifted by 90…”

Section: Introductionmentioning

confidence: 99%

Modelling and control of a travelling wave in a finite beam, using multi-modal approach and vector control method

Ghenna

Giraud

Giraud-Audine

et al. 2015

2015 Joint Conference of the IEEE International Frequency Control Symposium &Amp; The European Frequency and Time Forum

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. Abstract-This paper presents a new method to produce and control the vibration amplitude and direction of a travelling wave in a finite beam, using multi-modal approach. A closed loop control of the transducer vibration is applied using vector control method. the modelling in rotating frame and the decoupling according to two-axis allows to obtain a double independent closed loop control. This allows to regulate the vibration amplitude of the travelling wave directly. An analytical modelling is presented, with experimental validation, showing good performances even in the presence of perturbations.

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Excitation of a Progressive Wave in a Flexurally Vibrating Transmission Medium

Cited by 18 publications

References 0 publications

Turbulent Boundary Layer over a Piezoelectrically Excited Traveling Wave Surface

Turbulent Boundary Layer over a Piezoelectrically Excited Traveling Wave Surface

An object transport system using flexural ultrasonic progressive waves generated by two-mode excitation

Modelling and control of a travelling wave in a finite beam, using multi-modal approach and vector control method

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