• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.986-990
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• 2005

The present study aims to illuminate the vertical velocity profile of outer region of open-channel flow. Two sets of experiments were performed with PIV and propeller velocimeter. The first set was conducted to investigate the effect of bed roughness on the velocity distribution. The second set of experiments was carried out to find the effect of the Froude number on the velocity profile under the same bed roughness. The results reveal that the wake-law fits well with the experimental data from the bottom to the depth of maximum velocity, but it deviates from the experimental data above the maximum velocity point due to velocity-dip phenomenon, and that the velocity profile of the outer region is more influenced by the Froude number than the roughness. It is also shown that both the velocity difference between maximum velocity and surface velocity and the ratio of the average velocity to surface velocity become larger as the Froude number increases.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.4
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• pp.16-23
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• 1985

In case of tissue characterization from ultrasonic echo signal, it is difficult to evaluate an absolute physical quantity because of redundancy in the echo signal. For it, in this paper a possibility of characterization of ultrasonic velocity distribution in multilayered medium using dip points analysis method from the reflected echo spectrum is discussed. To prove the possibility of this method, effect of interference phenomenon, impedance difference, attenuation, and thickness is discussed by computer simulation, and then the results confirm the effectiveness. And results of simple experiment are presented.