Several numerical schemes for the computation of unsteady flow in pulsed lasers

Srivastava, B. N.; Waldman, G. D.; Cruickshank, J. O.; Moran, James P.

doi:10.2514/3.9710

Cited by 2 publications

(6 citation statements)

References 16 publications

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“…A similar detailed study of numerical issues related to algorithm, geometric, and boundary treatment errors was discussed in Ref. 10. Algorithm considerations, however, were restricted to early numerical methods.…”

Section: Introductionmentioning

confidence: 98%

“…Sidewall-muffler backing volume models were improved to include the full Euler equations with source terms. 10 This algorithm, however, suffered from several other deficiencies for laser applications. Computationally, this algorithm was found to be a factor of 2, or more expensive to run than the conventional explicit MacCormack's scheme.…”

Section: Introductionmentioning

confidence: 98%

“…The need to develop two-dimensional computational approaches for such problems brought forth a series of studies 10 in an effort to identify a suitable two-dimensional algorithm and models. At the time, proven existing discontinuity capturing algorithms, such as those of MacCormack, 11 Beam and Warming, 12 and SHASTA, 13 were investigated for suitable laser-related model problems.…”

Section: Introductionmentioning

confidence: 99%

“…At the time, proven existing discontinuity capturing algorithms, such as those of MacCormack, 11 Beam and Warming, 12 and SHASTA, 13 were investigated for suitable laser-related model problems. 10 Because of coding complexity, two-dimensional characteristics schemes were not investigated further. These studies suggested that a convective algorithm like SHASTA is superior to the other schemes just noted.…”

Section: Introductionmentioning

confidence: 99%

“…These studies suggested that a convective algorithm like SHASTA is superior to the other schemes just noted. 10 Two-dimensional SHASTA codes were then evolved that were primarily inviscid in nature. Sidewall-muffler backing volume models were improved to include the full Euler equations with source terms.…”

Section: Introductionmentioning

confidence: 99%

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High resolution computation of unsteady flows in pulsed lasers

et al. 1992

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A three-dimensional total variation diminishing (TVD) algorithm is developed for computing unsteady/steady flows in pulsed lasers. The general approach utilizes a three-dimensional thin-layer Navier-Stokes/Euler solver with source terms in the main channel, a one-dimensional Euler solver with source terms in the sidewall-muffler backing volume, and a quasisteady channel to backing volume flow-exchange model. Explicit time integration of these equations is accomplished via symmetric TVD formulations in an effort to enhance accuracy of the computed solution. Shock-tube experiments are performed to generate a data base for generic laser related problems and are shown to compare well with the computed solutions. Some aspects of laser flow/acoustic design are then discussed to demonstrate the capability of the code to supplement an overall flow system design effort. Nomenclature a -acoustic speed C d = discharge coefficient (muffler wall) K ml = normalized linear resistance in muffler backing volume, K m Llp r u r K mn = normalized nonlinear resistance in muffler backing volume, K mn L K r = normalized linear resistance of muffler wall, KJp r u r L = reference length p -dimensional pressure t -dimensional time u r -reference velocity, a 0 a = open area ratio (muffler wall) y = ratio of specific heats p r = reference density, p 0

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High resolution computation of unsteady flows in pulsed lasers

et al. 1992

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Numerical study of 2D and 3D flowfields in a high‐power pulsed chemical laser

Vuillon

Zeitoun²

1997

International Journal of Numerical Methods for Heat &Amp; Fluid Flow

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High‐power chemical lasers operating in high repetitive rate show a decrease of the output energy laser beam. In such lasers, the characteristic time which depends on the laser output is short in comparison with those related to the flow. Consequently, shock waves, acoustic waves and thermal perturbations, induced by the strong electric energy deposition and remaining in the laser cavity between two pulses, may explain the decrease of output energy of the laser beam. For a better understanding of the flowfields, a numerical approach is carried out using flux corrected transport algorithms (FCT methods) associated with a Riemann solver on the computational domain boundaries. Under two‐dimensional assumptions, the inviscid flow in the convergent‐divergent laser cavity is computed to describe the creation and propagation of the wave system and the hot gas column in both single and multidischarge operating modes. Distortions of the contact surfaces are put into evidence through the study of flowfield instabilities. Finally, the limitations of the two‐dimensional modelization become apparent. The numerical resolution is extended to a 3D case in order to take into account the optical direction. This allows to study the influence of shock waves travelling between optics and being generated by a side effect developing at the electrodes. These waves have an effect of long duration on the flowfield and lead to a high residual perturbation level.

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Several numerical schemes for the computation of unsteady flow in pulsed lasers

Cited by 2 publications

References 16 publications

High resolution computation of unsteady flows in pulsed lasers

High resolution computation of unsteady flows in pulsed lasers

Numerical study of 2D and 3D flowfields in a high‐power pulsed chemical laser

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