한국수자원학회논문집 (Journal of Korea Water Resources Association)

  • 제53권1호
  • /
  • Pages.15-27
  • /
  • 2020
  • /
  • 2799-8746(pISSN)
  • /
  • 2799-8754(eISSN)
한국수자원학회 (Korea Water Resources Association)
권호 표지
DOI QR코드

DOI QR Code

전자파표면유속계의 측정 각도에 따른 평수기 유속 측정 정확도 분석

Accuracy evaluation of microwave water surface current meter for measurement angles in middle flow condition

  • 손근수 (단국대학교 토목환경공학과) ;
  • 김동수 (단국대학교 토목환경공학과) ;
  • 김경동 (단국대학교 토목환경공학과) ;
  • 김종민 (한국건설기술연구원 하천연구센터)
  • Son, Geunsoo (Department of Civil & Environmental Engineering, Dankook University) ;
  • Kim, Dongsu (Department of Civil & Environmental Engineering, Dankook University) ;
  • Kim, Kyungdong (Department of Civil & Environmental Engineering, Dankook University) ;
  • Kim, Jongmin (River Experiment Center, KICT)
  • 투고 : 2019.10.29
  • 심사 : 2019.11.25
  • 발행 : 2020.01.31
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

하천 유량관측은 수자원의 관리를 위해 활용되는 기초적이고 대표적인 자료로 하천에서 정확한 유량을 관측하는 것은 중요하다. 따라서 최근에는 다양한 첨단 장비들이 개발되어 전통적인 하천의 유량관측을 대체하거나 보완하고 있다. 여러 최신 장비들 중 전자파표면유속계는 홍수기와 같이 하천에 접근하여 직접유량계측이 위험하고 정확도 확보가 어려울 경우전자파를 이용하여 비접촉식으로 유량을 계측하는 장비로 홍수기 및 평갈수기에도 하천 유량계측에 활용되기 시작하였다. 전자파표면유속계는 사용법이 간단하고 간접적으로 유속을 측정하기 때문에 기존의 직접측정 방법에 비해 안전한 장점이 있어 현재 국내에서는 홍수기 또는 접근이 어려운 하천의 유속 측정을 위해 사용되고 있다. 국내에서는 1993년 유량측정 장치 개발을 위해 전자파표면유속계(MWSCM; Microwave Water Surface Current Meter)를 개발을 연구를 수행하였고, 최근에는 국내에서 개발된 전자파표면유속계을 활용하여 유량측정을 위해 사용되고 있다. 하지만 국내에서 개발된 전자파표면유속계가 실제 하천에서 유속측정의 정확도에 대한 연구는 부족한 실정이다. 전자파표면유속계는 기기로부터 전자파를 이용해 유속을 측정하기 때문에 수직각과 편각과 같은 각도 변화에 따라 측정정확도가 바뀔 수 있고, 전자파표면유속계 본체에서 발사되는 전자파의 측정영역에 따라 유속측정에 오차가 발생할 수 있다. 본 연구에서는 국내에서 개발 전자파표면유속계의 측정정확도를 분석하기 위해서 실제하천과 유사한 실규모 하천수로에서 수직각과 편각을 변화시키며 측정을 수행하여 수직각과 편각에 변화에 따른 유속측정 정확도를 분석하였다. 그리고 전자파표면유속계의 측정영역의 고려를 통해서 측정영역에 따른 유속측정결과를 분석하였다. 유속측정 결과를 통해서 수직각 15° 이하에서는 유속측정의 오차가 커지게 되는 것으로 나타났고, 편각이 커질수록 유속측정의 결과의 변동계수가 커지는 것으로 나타났다. 그리고 편각에 따른 오차의 영향은 전자파표면유속계의 측정영역에 따라 결과가 달라지는 것으로 나타났다.

Streamflow discharge as a fundamental riverine quantity plays a crucial role in water resources management, thereby requiring accurate in-situ measurement. Recent advances in instrumentations for the streamflow discharge measurement has complemented or substituted classical devices and methods. Among various potential methods, surface current meter using microwave has increasingly begun to be applied not only for flood but also normal flow discharge measurement, remotely and safely enabling practitioners to measure flow velocity postulating indirect contact. With minimized field preparedness, this method facilitated and eased flood discharge measurement in the difficult in-situ conditions such as extreme flood in active ways emitting 24.125 GHz microwave without relying on natural lights. In South Korea, a rectangular shaped instrument named with Microwave Water Surface Current Meter (MWSCM) has been developed and commercially released around 2010, in which domestic agencies charging on streamflow observation shed lights on this approach regarding it as a potential substitute. Considering this brand-new device highlighted for efficient flow measurement, however, there has been few noticeable efforts in systematic and comprehensive evaluation of its performance in various measurement and riverine conditions that lead to lack in imminent and widely spreading usages in practices. This study attempted to evaluate the MWSCM in terms of instrumen's monitoring configuration particularly regarding tilt and yaw angle. In the middle of pointing the measurement spot in a given cross-section, the observation campaign inevitably poses accuracy issues related with different tilt and yaw angles of the instrument, which can be a conventionally major source of errors for this type of instrument. Focusing on the perspective of instrument configuration, the instrument was tested in a controlled outdoor river channel located in KICT River Experiment Center with a fixed flow condition of around 1 m/s flow speed with steady flow supply, 6 m of channel width, and less than 1 m of shallow flow depth, where the detailed velocity measurements with SonTek micro-ADV was used for validation. As results, less than 15 degree in tilting angle generated much higher deviation, and higher yawing angle proportionally increased coefficient of variance. Yaw angles affected accuracy in terms of measurement area.

키워드

참고문헌

  1. Bathurst, J.C. (1997). "Environmental river flow hydraulics." Applied fluvial geomorphology for river engineering and management, pp. 69-93.
  2. Corato, G., Moramarco, T., and Tucciarelli, T. (2011). "Discharge estimation combining flow routing and occasional measurements of velocity." Hydrology and Earth System Sciences, Vol. 15, No. 9, pp. 2979-2994. https://doi.org/10.5194/hess-15-2979-2011
  3. Costa, J.E., Cheng, R.T., Haeni, F.P., Melcher, N., Spicer, K.R., Hayes, E., Plant, W., Hayes, K., Teague, C., and Barrick, D. (2006). "Use of radars to monitor stream discharge by noncontact methods." Water Resources Research, Wiley, Vol. 42, No. 7.
  4. Decatur Electronics (2011). SVR (Surface Velocity Radar) User's Manual. Decatur Electronics Europe Inc.
  5. Dramais, G., Le Coz, J., Camenen, B., and Hauet, A. (2011). "Advantages of a mobile LSPIV method for measuring flood discharges and improving stage-discharge curves." Journal of Hydro-Environment Research, Elsevier, Vol. 5, No. 4, pp. 301-312. https://doi.org/10.1016/j.jher.2010.12.005
  6. Fujita, I., Watanabe, H., and Tsubaki, R. (2007). "Development of a non-intrusive and efficient flow monitoring technique: The space-time image velocimetry (STIV)." International Journal of River Basin Management, Vol. 5, No. 2, pp. 105-114. https://doi.org/10.1080/15715124.2007.9635310
  7. Fukami, K., Yamaguchi, T., Imamura, H., and Tashiro, Y. (2008). "Current status of river discharge observation using non-contact current meter for operational use in Japan." In World Environmental and Water Resources Congress 2008: Ahupua'A, pp. 1-10.
  8. Fulton, J., and Ostrowski, J. (2008). "Measuring real-time streamflow using emerging technologies: Radar, hydroacoustics, and the probability concept." Journal of Hydrology, Elsevier, Vol. 357, No. 1-2, pp. 1-10. https://doi.org/10.1016/j.jhydrol.2008.03.028
  9. Keulegan, G.H. (1938). "Laws of turbulent flow in open channels." US: National Bureau of Standards, Vol. 21, pp. 707-741.
  10. Kim, D.S., Yang, S.K., and Jung, W.Y. (2014). "Error analysis for electromagnetic surface velocity and discharge measurement in rapid mountain stream flow." Journal of Environmental Science International, Vol. 23, No. 4, pp. 543-552. https://doi.org/10.5322/JESI.2014.4.543
  11. Kim, Y.S., Won, N.I., Noh, J.W., and Park, W.C. (2015). "Develop ment of high-performance microwave water surface current meter for general use to extend the applicable velocity range of microwave water surface current meter on river discharge measurements." Journal of Korea Water Resources Association, KWRA, Vol. 48, No. 8, pp. 613-623. https://doi.org/10.3741/JKWRA.2015.48.8.613
  12. Kim. S.J., Yu, K.K., and Yoon, B.M. (2011). "Real-Time Discharge Measurement of the River Using Fixed-type Surface Image Velocimetry." Journal of Korea Water Resources Association, KWRA, Vol. 44, No. 5, pp. 377-388. https://doi.org/10.3741/JKWRA.2011.44.5.377
  13. Le, Coz, J., Hauet, A., Pierrefeu, G., Dramais, G., and Camenen, B. (2010). "Performance of image-based velocimetry (LSPIV) applied to flash-flood discharge measurements in Mediterranean rivers." Journal of hydrology, Elsevier, Vol. 394, No. 1-2, pp. 42-52. https://doi.org/10.1016/j.jhydrol.2010.05.049
  14. Lee, J.S., and Julien, P.Y. (2006). "Electromagnetic wave surface velocimetry." Journal of hydraulic engineering, ASCE, Vol. 132, No. 2, pp. 146-153. https://doi.org/10.1061/(ASCE)0733-9429(2006)132:2(146)
  15. Lee, S.H., Kim, U.G., and Kim, Y.S. (1997). "Practical aspects of microwave surface velocity meter applied to measurements of stream discharges." Journal of Korea Water Resources Association, KWRA, Vol. 30, No. 6, pp. 671-678.
  16. Lee, S.H., Lee, H.G., and Kim, U.G. (1995). "Velocity measure ment of stream water surface using microwave." Water for future, KWRA, Vol. 28, No. 6, pp. 183-191.
  17. Mueller, D.S., Wagner, C.R., Rehmel, M.S., Oberg, K.A., and Rainville, F. (2009). Measuring discharge with acoustic Doppler current profilers from a moving boat. United States Geological Survey: Reston, WV, USA 2009.
  18. Muste, M., Fujita, I., and Hauet, A. (2008). "Large-scale particle image velocimetry for measurements in riverine environments." Water resources research, Wiley, Vol. 44, No. 4.
  19. Mutronics (2011). User's Manual. Mustronics.
  20. Nezu, I., and Nakagawa, H. (1993). "Turbulence in open channel flows." IAHR Monograph, A. A. Balkema, Rotterdam.
  21. Nezu, I., and Rodi, W. (1986). "Open-Channel flow measurements with a laser doppler anemometer." Journal of Hydraulic Engineering, ASCE, Vol. 112, No. 5, pp. 335-355. https://doi.org/10.1061/(ASCE)0733-9429(1986)112:5(335)
  22. Plant, W.J., Keller, W.C., and Hayes, K. (2005). "Measurement of river surface currents with coherent microwave systems." IEEE Transactions on Geoscience and Remote Sensing, Vol. 43, No. 6, pp. 1242-1257. https://doi.org/10.1109/TGRS.2005.845641
  23. Sontek (1997). Acoustic Doppler Velocitmetry Operation Manual, Firmware version 4.0. Sontek, San Diego.
  24. Sontek (2009). FlowTracker. Handheld ADV. User's Manual. Sontek, San Diego.
  25. Steffler, P.M., Rajaratnam, N., and Peterson, W. (1985). "LDA measurements in open channel." Journal of Hydraulic Engineering, ASCE, Vol. 111, No. 1, pp. 119-130. https://doi.org/10.1061/(ASCE)0733-9429(1985)111:1(119)
  26. Szupiany, R.N., Amsler, M.L., Best, J.L., and Parsons, D.R. (2007). "Comparison of fixed-and moving-vessel flow measurements with an aDp in a large river." Journal of Hydraulic Engineering, ASCE, Vol. 133, No. 12, pp. 1299-1309. https://doi.org/10.1061/(ASCE)0733-9429(2007)133:12(1299)
  27. Tamari, S., Garcia, F., Arciniega-Ambrocio, J.I., and Porter, A. (2014). "Testing a handheld radar to measure water velocity at the surface of channels." La Houille Blanche, No. 3, pp. 30-36.
  28. Tennekes, H., Lumley, J.L., and Lumley, J.L. (1972). "A first course in turbulence." MIT press, Massachusetts.
  29. Yang, S.K., Kim, D.S., Jung, W.Y., and Yu, K.K. (2011). "Analysis and comparison of stream discharge measurements in Jeju island using various recent monitoring techniques." Journal of Environmental Science International, Vol. 20, No. 6, pp. 783-788. https://doi.org/10.5322/JES.2011.20.6.783
  30. Yang, S.K., Kim, D.S., Yu, K.K., Kang, M.S., Jung, W.Y., Lee, J.H., Kim, Y.S., and You, H.J. (2012). "Comparison of flood discharge and velocity measurements in a mountain stream using electromagnetic wave and surface image." Journal of Environmental Science International, Vol. 21, No. 6, pp. 739-747. https://doi.org/10.5322/JES.2012.21.6.739