| 1. |
- Field, J.E., et al.
(author)
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On the mechanics of high speed liquid jets
- 1977
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In: Proceedings of The Royal Society of London. Series A, Mathematical and physical sciences. - : The Royal Society. - 0080-4630. ; 357:1689, s. 143-162
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Journal article (peer-reviewed)abstract
- Both experimental and theoretical methods are used to investigate the mechanics of the emergence and flight of a liquid jet travelling at speeds supersonic relative to the sound speed of the liquid. The experimental work uses an Imacon image converter camera to follow the mechanical events at micro-second framing intervals. The theoretical investigation employs similarity arguments and the Tschaplygin transformation to investigate the role of liquid overcompression in the process of the jet emergence. In addition, simple theoretical arguments are used to examine the effects of Stokes drag on the small liquid particle shroud surrounding the jet and Taylor instability effects in the late time history of the jet’s flight. An evacuated chamber is used to verify the theoretical prediction that subsonic (relative to the liquid sound speed) jets will not undergo the violent decompression process predicted for supersonic jets. The experimental and theoretical evidence are synthesized into an overall picture of the jet’s history from initial decompression of an overdense supersonic jet to the breakup of the resulting liquid slugs by deceleration and Taylor instability.
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| 2. |
- Lesser, Martin
(author)
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Fluid mechanics of liquid drop impact with rigid surfaces
- 1979
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In: Proceedings of the Fifth International Conference on Erosion by Liquid and Solid Impact : Newnham College, Cambridge, UK, 3 - 6 September 1979. - Cambridge : Cavendish laboratory univ.. ; , s. 1.1-1.7
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Conference paper (peer-reviewed)abstract
- A theory is presented for the fluid mechanical aspects of the impact of liquid drops, with rounded fronts, with a rigid surface. It is shown that for small collision Mach number (which corresponds to collisions under 300 m/s for water drops) there is a time period from a fraction of a microsecond after impact to several microseconds where an asymptotic expansion for small Mach number yields both complete and simple results. Explicit equations for the pressure at the interface are derived for both the two and three dimensional circular and spherical drop. Results are compared with other work. The asymptotic expansion procedure is interpreted in physical terms and suggestions for extensions of the present work are discussed
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| 3. |
- Lundberg, Bengt, et al.
(author)
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Determination of the distributed parameters of a lossless wave supporting system from boundary measurements
- 1977
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In: Applied Scientific Research. - 0003-6994 .- 2212-0939. ; 33:2, s. 151-162
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Journal article (peer-reviewed)abstract
- A lossless wave supporting system is modelled by two linear partial differential equations with variable coefficients α(x) and β(x), x⩾0, which represent the distributed parameters of the system. The problem of determining α(x) and (x) from measurements performed at the boundary x=0 is considered. It is shown that generally it is only possible to determine an impedance function Z¯(ξ), where Z¯ and ξ depend on α and β. If some additional relationship is known between α and β, however, it may be possible to fully determine these parameters. This is the case if, for example, it is known that the wave speed is constant
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| 4. |
- Lundberg, Bengt, et al.
(author)
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Impacor synthesis
- 1978
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In: Journal of Sound and Vibration. - 0022-460X .- 1095-8568. ; 58:1, s. 5-14
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Journal article (peer-reviewed)abstract
- A method for synthesizing non-uniform, linearly elastic impactors which generate given impact forces on given targets is presented. The impactors are assumed to obey Webster's equation, and the targets are assumed to be linear with time-invariant properties. The method is illustrated by solving two synthesis problems concerned with the generation of exponential and ramp impact loads. The results are verified by solving the corresponding analysis problems.
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