Acoustic shaping in microgravity

Wanis, Sam; Akovenko, J.; Cofer, T.; Ames, Richard; Komerath, Narayanan

doi:10.2514/6.1998-1065

Cited by 15 publications

(14 citation statements)

References 4 publications

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“…• The Georgia Tech Microgravity student flight team [6], as discussed above, developed Acoustic Shaping technology to form complex shapes using large numbers of solid particles in air, in a rectangular chamber. The particles used had random shape in one case (styrofoam pieces), and quasi-ellipsoidal shape in the other (Kellogg's Rice Crispies Cereal).…”

Section: Issuesmentioning

confidence: 99%

“…Work on acoustic "levitation" has progressed since the late 19 th century [5], when observations were reported of coal dust accumulating in heaps at locations corresponding to the nodes of sound fields in mine shafts. A brief survey of the patents related to acoustic positioning was given in [6]. Wang [4] summarized the NASA program directed at acoustic positioning.…”

Section: Introductionmentioning

confidence: 99%

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Acoustic shaping in microgravity - Higher order surface shapes

Wanis

Sercovich

Komerath

1999

37th Aerospace Sciences Meeting and Exhibit

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Further results from microgravity flight experiments on acoustic shaping are discussed. In previous experiments, the authors showed that straight and curved walls could be formed using styrofoam and cereal pellets of arbitrary shape seeded in a sound field in a resonant chamber. The wall shapes corresponded to constant-pressure-amplitude contours of the sound field; however, the walls have multiple stable locations near the nodal planes. Low acoustic energy input found to be sufficient in microgravity. Here the observations are related to predictions of particle and flowfield behavior. For the low-order modes used here, acoustic streaming is an important factor in transporting particles through the chamber. Simulations using multiple harmonics indicates possibilities for constructing and transporting shapes inside the container. Flow visualization supports the streaming predictions. The streaming velocity corresponds to the predicted values for the measured standing wave pressure amplitude. Visualizations of nodal planes show the formation of shapes of specified curvature. G-jitter is of the order of 0.03g, comparable to the peak accelerations due to acoustic radiation force, limits wall formation and control time during each parabola. Complex shapes can be formed with a variety of materials in microgravity. Tailoring the sound field to specific shapes and materials appears to be within reach.

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Section: Issuesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Acoustic shaping in microgravity - Higher order surface shapes

Wanis

Sercovich

Komerath

1999

37th Aerospace Sciences Meeting and Exhibit

Self Cite

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“…This poses a drawback in dealing with raw material until powerful long-wave resonators can be developed, or we learn to generate adequate coherent forces in the Mie scattering regime. To-date, as seen from Table 3.1, the Rayleigh-domain experimental data are in the acoustic regime with millimeter-scale objects [23][24][25][26][27][28][29][30][31][32][33][34][35] and the optical regime with nanometer-scale objects [10]. The above results indicate that high microwave intensity would be required to move particles.…”

Section: Generalized Relationsmentioning

confidence: 99%

“…We [23] Our approach in this chapter starts from the observation that the equations describing the generation of radiation forces and trapping stiffness in optics and acoustics are similar. We confirmed this similarity through results from flight and ground experiments using audible sound, comparing them with results from optics and ultrasonics in other wavelength and size regimes.…”

Section: Previous Workmentioning

confidence: 99%

Tailored Force Fields for Space-Based Construction

Komerath

Wanis²,

Czechowski³

2003

AIP Conference Proceedings

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“…The similarity between the governing equations for acoustic and electromagnetic force generation was shown, and used to develop a scaling relationship for the acceleration per unit intensity, experienced by particles of given materials (Komerath, Wanis, and Czechowski, 2003). Experimental evidence was then used to compare the forces on millimeter-sized particles in resonant acoustic fields (Wanis et al 1998;Wanis, Sercovich, and Komerath, 1999;Wanis, Matos and Komerath, 2000) to micron-sized particles in visible-range laser beams (Ashkin, 2000;Rohrbach and Stelzer, 2001;Grier, 2003;Zhan, 2003). In subsequent work we (Wanis and Komerath, 2004) explored the influence of the particle material properties, and the separation of wavelengths needed for formation of walls, versus those for heating and sintering the surfaces.…”

Section: Introduction and Scopementioning

confidence: 99%

Particle-Particle Interaction in Electromagnetic Fields for Force-Field Tailoring

Wanis¹,

Rangedera²,

Komerath³

2007

AIP Conference Proceedings

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Tailored electromagnetic force fields offer the possibility of forming structures ranging in size from micrometers to kilometers from loose particles. In prior work, the analogy between primary radiation forces in acoustics and electromagnetics was used to develop and validate a scaling relationship in the Rayleigh regime. This scaling indicated that a 100m x 100m radio-frequency solar-powered resonator could form radiation-shielded structural modules large enough for human habitation. Force predictions on a single particle in a microwave field have been experimentally validated. In this paper, secondary forces due to particle interaction are linked to first principles, and a dipole model is used to facilitate solutions. Secondary forces are shown to determine the shape of structures formed. The dipole model serves to illustrate similarities and differences between acoustic and electromagnetic fields. The nature of the dipole interaction shows that walls form naturally in acoustic fields. In electromagnetic fields, chains can be formed, with walls or other structures formed from these chains. Finite element simulations are used to derive interesting field patterns using given combinations of low-order modes. A 2-dimensional time-stepping calculation shows chains forming in given fields, while a 3-dimensional calculation shows small chains forming into more complex structures. Thus the force-field tailoring problem is reduced to one represented by well-known equations and solution techniques for both primary and secondary forces.

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Acoustic shaping in microgravity

Cited by 15 publications

References 4 publications

Acoustic shaping in microgravity - Higher order surface shapes

Acoustic shaping in microgravity - Higher order surface shapes

Tailored Force Fields for Space-Based Construction

Particle-Particle Interaction in Electromagnetic Fields for Force-Field Tailoring

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