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<p>Hybrid pulse-burst Doppler global velocimetry/pulse-burst, cross-correlation Doppler global velocimetry was demonstrated for the first time in the NASA Langley 4-foot Supersonic Unitary Plan Wind Tunnel, allowing simultaneous acquisition of mean and instantaneous high-repetition-rate velocity fields. The technique was used to make planar velocity measurements across an oblique shockwave generated by a large splitter plate set at a − 2° angle of attack in a Mach 2.4 flow. Sequences of more than 100 consecutive instantaneous velocity fields were obtained at a rate of 100&#xa0;kHz. Velocity fields from both the mean and instantaneous measurements from the hybrid technique indicated errors less than 1 percent of anticipated velocities. Likewise, assessment of measurement precision yielded velocity measurements of approximately 1.6 percent of the local velocities. Additional demonstrations in different flowfields including a subsonic axisymmetric jet and a supersonic Mars reentry vehicle model further illustrate the utility of the new hybrid method. Evaluation of these other test cases indicated the potential for retroactive extraction of unsteady velocity information from previously acquired mean data.</p> Graphic abstract <p></p>

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Hybrid pulse-burst/cross-correlation Doppler global velocimetry for high-speed velocity measurements at 100 kHz

  • 期刊论文

  • 发表日期：

    2025年11月6日

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  • Ross A. Burns,
  • Timothy W. Fahringer Jr.,
  • Paul M. Danehy

摘要

Hybrid pulse-burst Doppler global velocimetry/pulse-burst, cross-correlation Doppler global velocimetry was demonstrated for the first time in the NASA Langley 4-foot Supersonic Unitary Plan Wind Tunnel, allowing simultaneous acquisition of mean and instantaneous high-repetition-rate velocity fields. The technique was used to make planar velocity measurements across an oblique shockwave generated by a large splitter plate set at a − 2° angle of attack in a Mach 2.4 flow. Sequences of more than 100 consecutive instantaneous velocity fields were obtained at a rate of 100 kHz. Velocity fields from both the mean and instantaneous measurements from the hybrid technique indicated errors less than 1 percent of anticipated velocities. Likewise, assessment of measurement precision yielded velocity measurements of approximately 1.6 percent of the local velocities. Additional demonstrations in different flowfields including a subsonic axisymmetric jet and a supersonic Mars reentry vehicle model further illustrate the utility of the new hybrid method. Evaluation of these other test cases indicated the potential for retroactive extraction of unsteady velocity information from previously acquired mean data.

Graphic abstract