유출수(流出水) 및 유실토량(流失土量) 측정장치(測定裝置)에 관(關)한 수리시험(水理試驗)

유한열 ( Han Yeol Ryu ),정하우 ( Ha Woo Chung ) 한국농공학회 1968 韓國農工學會誌 : 전원과 자원 Vol.10 No.2

In order to measure runoff and soil losses produced in a small test plot during rainfall, it is usually insu-fficient to use a tank only, necessitating the combined use of a main tank and a subsidiary tank. Accordingly. exact measurement largely depends on how to connect those two measuring tanks. The main purpose of this thesis is to improve the connecting parts of two measuring tanks so as to assure exact measurement of runoff and soil losses. In this experiment, two types of main tank, i. e. A-type and B-type, were used. A-type is a square tank having a flume at its end. At the flume, ten apertures are provided by using metal columns so as to be able to catch one tenth of total muddy flow discharging at the end of the flume, One tenth of total flow is led to the subsidiary tank through a slot sampler fixed to an aperture. B-type differes in that its flume does not have apertures and slot sampler is fixed directly to the end of the flume, other features being the same as those of A-type. Discharge volumes were measured by using weighing tanks and compared. The effect of baffle screen provided in the flume was also observed in connection with exact measurements. In order to keep main tank and its flume in a horizontal position, bolts and nuts mechanism was used. Vertical and horizontal screens were provided in the main to prevent coarse sands coming into the flume. The conclusion derived through this experiment is as follows: (1) The discharge through slot sampler at each aperture is almost the same for A-type. However, it is slightly more than one tenth of total discharge volume. (2) In case that baffle screen is provided in the flume of A-type tank, the discharge volume of slot sampler is less than that of the same type without screen. (3) For B-type tank, slot sampler discharge increases as slot sampler nears toward the center of flume. (4) When baffle screen is provided in the flume of B-type, slot sampler discharge is less than that of the same type without screen, and this phenomenon is more apparent as compared with A-type. (5) In case that the slot width of slot sampler for B-type is one inch, slot sampler discharge exceeds one tenth of total discharge volume. (6) When the slot width for B-type is 15/16 inch and slot sampler is fixed 3/8 inch apart from either flume wall, slot sampler discharge is approximately equal to one tenth of total discharge volume.

전작물(田作物)의 관개법(灌漑法)에 관(關)한 비교연구(比較硏究)(I)

유한열 ( Han Yeol Ryu ),고재군 ( Chae Koon Koh ) 한국농공학회 1969 韓國農工學會誌 : 전원과 자원 Vol.11 No.1

In this experiment furrow and fixed nozzle methods in irrigating chiness cabbages were compared on the grounds of yields and amounts of irrigation water. A simple electric device was used to measure soil moisture contents. As a result, the following items were derived: 1) A slight significance was observed between the yield produced at the furrow irrigation test plot and that at the sprinkler irrigation plot. 2) The ratio of the amount of irrigation water applied at the furrow irrigation plot to that at the sprinkler irrigation plot was approximately 2.7 : 1.

윤환관개방법과 적정시설 연구

유한열 ( Han Yeol Ryu ),정하우 ( Ha Woo Chung ) 한국농공학회 1971 韓國農工學會誌 : 전원과 자원 Vol.13 No.1

In this research, Nong-rim No. 6 was adopted as a test variety of rice. Rice seedlings were transplanted on June 14, 1970. Roots were settled into soil on June 20 and a total number of days irrigated of 21 cm×21cm and an area of 9.9㎡ for a test plot were accepted, planting 70 stumps of rice in a test plot. The soil in test plots are classified by soil test as oam, and its chemical contents are as shown in Table 3. Irrigation water was secured by pumping from the Sudun stream that originates at the Suho reservoir. Accordingly, the qualities of irrigation, water are considered to be the same as those of water stored in the Suho reservoir. There were 54 days of intermittent rainfalls in total during the whole 110-day period of irrigation. As a result, it is likely that the growth of rice plants was influenced by rainfall at a comparatively great degree. In order to measure the amounts of water consumption, infiltrometers, measuring devices for the decreases of water depths and lycimeters were provided. As a result of measurements, an average daily rate of infiltration was observed to be 14mm/day. It is expected from this research that the effect of increased yield will be secured by supplying optimum amounts of water for irrigation on proper times, and that the amounts of water consumption for irrigation can be saved by applying suitable irrigation methods. The test results obtained are summarized as follows: 1. Yields produced in the test plots of continuous irrigation are lower than those in the test plots of rotational irrigation, i.e., yields produced at the test plots irrigatied once in a period of 8 days are higher by 27% in average than those produced at test plots of continuous irrigation. 2. The amounts of irrigation water for test plots, which have a clay layer of 9cm in thickness and vynil diaphragm without holes, are saved by about 52% in comparison with ordinary test plots. 3. Ears are sprouted 5 days earlier at continuous irrigation plots as compared with other test plots. 4. It seems that there are growing stages of rice plants such as those of forming and sprouting of ears, in which the amounts of irrigation water are consumed more in comparison with the other stages. Therefore, it may be possible to increase or decrease the amount of irrigation water, according to the growing stage of rice plant, so as to save irrigation water.

경사지(傾斜地) 상전(桑田)에 있어서 토양침식방지법(土壤侵蝕防止法)의 비교시험

유한열 ( Han Yeol Ryu ) 한국농공학회 1968 韓國農工學會誌 : 전원과 자원 Vol.10 No.1

The purpose of this experiment is to measure runoffs and soil losses produced in mulberry test plots so as to determine their differences for different planting densities of mulberry saplings. Test plots were prepared on a 22° slope by applying semi-terrasing method as proposed by the Sericulture Experiment Station of the Office of Rural Development. Two planting densities were selected. One was to plant mulberry rows 1. 8 Meters apart and the other was 2.1 meters apart. 1) The following results were obtained through this experiment in the first year. Total runoffs were 92. 39 tons/10a from the 1.8-m plot and 95. 62 ton/10a from the 2.1-m plot, showing a silte difference. Total soil losses were 1.69 tons/10a from the former and 2.33 ton/10a from the latter, showing some difference. 2) Runoff rates are 23% for the 1.8-m plot and 24% for the 2. 1m plot.

단면조절관(斷面調節管)-간단(簡單)한 교시용(敎示用) 수리시험(水理試驗) 장치(裝置)

유한열 ( Ryu Han Yeol ) 한국농공학회 1968 韓國農工學會誌 : 전원과 자원 Vol.10 No.2

Some simple devices to demonstrate important hydraulic principles are required in fluid mechanics or hy-draulics classes. Those devices should be easy to make and operate with inexpensive cost. The writer has studied some simple demonstration apparatus of hydraulic principles which were made of cheap materials. An adjustable nozzle is one of them. It can be connected to an axial flow fan so as to use air flow. By operating this apparatus, pressure changes in gradually enlarged or contracted conduits could be observed.

한계소유력(限界掃流力) 개념(槪念)에 의(依)한 안전개수로(安全開水路) 설계법(設計法)

유한열 ( Han Yeol Ryu ),박승우 ( Seung Woo Park ) 한국농공학회 1973 韓國農工學會誌 : 전원과 자원 Vol.15 No.3

한개용수량(漢槪用水量)의 수리적(水理的) 측정장치(測定裝置)에 관(關)한 실험(實驗)

이창구 ( Chang Koo Lee ),유한열 ( Han Yeol Ryu ),이상명 ( Sang Myung Lee ) 한국농공학회 1965 韓國農工學會誌 : 전원과 자원 Vol.7 No.1

The purpose of this paper is to study hydraulic devices to measure irrigation water. Those devices should be simple and inexpensive to make and operate. Sharp-edged weirs were mainly made of wooden planks and they are portable. A Ventri flume was also made of wooden planks that was painted with coal tar. Two stilling wells with scales on their walls to measure heads were attached to it, A cylinder-propeller flow meter was newly designed and made. It has a gear mechanism and a propeller in a 4-inch cylinder. It was rated under the condition of free outflow. This device will be useful to measure a definite quantity of irrigation water, automatically [closing its gate after passing the necessary quantity of water through it.

흙 수로(水路)에 대(對)한 삼투손실량(渗透損失量) 추정(推定)에 관(關)한 실험적(實驗的) 연구(硏究)

정하우 ( Har Woo Jung ),유한열 ( Han Yeol Ryu ) 한국농공학회 1973 韓國農工學會誌 : 전원과 자원 Vol.15 No.1

Models of cross-sections and channels were made in order to measure seepage losses. Cross-sections were made of sand, sandy clay loam and loam, their thicknesses being 30cm and 40cm, respectively. Flow depths kept in the cross-sections were 4cm, 6cm, 8cm and 10cm. Straight and curved channel models were provided so as to measure seepage losses, when constant water depths maintained at the heads of the channels were 7.3cm and 5.7cm, respectively. The results obtained in this experiment are presented as follows: 1) A cumulative seepage loss per unit length at a point in the channel varies in accordance with time and flow depth. The general equation of cumulative seepage loss may be as follows (Ref. to Table V.25): 2) In case that the variation of water depth through the channel is slight, the total seepage loss may be computed by applying the following general equation: 3) Because seepage loss varies considerably according to water depth in case that the variation of flow depth through the channel is great, seepage loss should be computed by taking account of the change of flow depth. 4) The relation between time and traveling distance of water flow may be presented as the following general equation (Ref. to Table V.29): 5) The ratios of the seepage losses of the straight channel to the curved channel are 1:1.03 for a flow depth of 7.3cm and 1:1.068 for that of 5.7cm. 6) The ratios of the seepage losses occurring through the bottom to those through the inclined plane in the channel cross-section are 1:2.24 for a water depth of 8cm and 1:2.47 for a depth of 10cm in case that soil-layer is 30cm in thickness. Similarly, those ratios are 1:2.62 and 1:2.93 in case of a soil-layer thickness of 40cm (Ref. to Table V.5).

Well Screen의 구조(構造)가 양수량(揚水量)에 미치는 영향(影響)

최예환 ( Choi Ye Hwan ),유한열 ( Han Yeol Ryu ) 한국농공학회 1967 韓國農工學會誌 : 전원과 자원 Vol.9 No.1

The purpose of this thesis is to study the correlations between the capacity and function of well screen, and the size of hole made in its wall and the ratio of the total area of holes, through which water flows into the well, to the cross-sectional area of well screen. In addition, the effect of gravel packing around well screen on the pumping rate of water is also observed. The conventional method to make well screen is that many holes are bored arbitrarily at the lower end portion of pipe without any standard with respect to the size and area of holes. Then, the whole pipe is simply driven into the ground up to the water-bearing layer by striking, twisting, etc. Therefore, it is necessary to give some standard with relation to holes bored in the wall of pipe. The pipe to make well screen in this experiment was plastic pipe, one inch in diameter. The water-bearing layer was made with sand obtained in the Sudun River in Suwon, and a model stratum was constructed by using the sample sand in the water tank with glass walls. The model of well screen which was half cylinder was as fixed on the wall of water tank. There are four types of well screens, each type having six ratios of the total area of holes to the cross-sectional area of well screen. Those six ratios are N=1/4, 1/2, 1, 1.5, 2 and 3 for the A-, B-, C- and D-type. The total number of test runs were 28 times for the A-, B-, C-, D- and B’-type of well screens, where the B’-type was the B’-type with gravels packed around it. Pipe used to pump water in the screen was glass pipe with 2. 5mm. in inside diameter, it being U-shaped. The length of one banch of glass pipe is 35.8 cm. which is the same height as that of water tank and the other 115.0 cm. In order to establish uniform soil compaction in the tank, an amount of 7,000 cc. of water was poured into the soil in the tank and pumped water out through well screen. This procedure was rep elated ten times. To test each type of well screen, an amount of 5, 000 cc of water was poured into the water tank and then pumping was measured by using mass cylinder. The conclusions as obtained in this experiment are presented as follows; 1. Filling gravels around well screen has better effect on pumping rate than filling natural soil. 2. The ratio of the total area of holes in well screen to its cross-sectional area should be approximately one. The heigher ratio than one does not result in more pumping rate. 3. In order to give some room when some holes are clogged, the above-mentioned ratio can be made 1.5 to 2 without weakening the strength of well screen. 4. Well screen must be provided with metal meshes to exclude silt, day and sand. 5. When a well pipe is driven into the ground by impaction, the distances between holes are so far away that he strength of well screen must stand against impaction. The distances between holes differ according to the thickness of wall of pipe.

수환관개(輸換灌漑)의 방법(方法)의 차이(差異)가 수도생육(水稻生育) 및 수량(收量)에 미치는 영향(影響)과 그 적정시설(適正施設)에 관(關)한 연구(硏究)

이창구 ( Chang Ku Rhee ),유한열 ( Han Yeol Ryu ) 한국농공학회 1969 韓國農工學會誌 : 전원과 자원 Vol.11 No.1

This experiment was conducted, making use of the 'NONG-RIM6' arecommended variety of rice for the year of 1968. Main purposes of the experiment are to explore possibilities of; a) ways and means of saving irringation water and, b) overcoming drought at the same time so that an increased yield in rice could be resulted in. Specifically, it was tried to determine the effects of the Rotation irrigation method combined with differentiated thickness of lining upon the growth and yield of rice. Some of the major findings are summarized in the following. 1) The different thicknesses show a significant relationship with the weight of 1,000 grains. In the case of 9cm lined plot, the grain weight is 23.5grams, the heaviest. Next in order is 3cm lined plot, 6cm lined plot, control plot, and wheat straw lined-plot. 2) In rice yield, it is found that there is a considerably moderate significant relationship with both the different thickness of lining and the number of irrigation, as shown in the table. 3) There is little or no difference among different plots in terms of a) physical and chemical properties of soil, b) quality of irrigation water, c) climatic conditions, and rainfalls. 4) It is found that there is a significant relationship between differences in the method of rotation irrigation and the number of ears per hill. The plot irrigated at an interval of 7 days shows 17.4 ears and plot irrigated at an interval of 6 days, 16.3. 5) In vinyl-treated plots, it is shown that both yield and component elements are greatest in the case of the plot ith whole of 3㎝/㎡ Next in order are the plot with a hole of 2㎝/㎡ the plot with a hole of 1㎝/㎡ In the case of the plot with no hole it is found that both yield and component elements are decreased as compared to the control plot. 6) The irrigation water reqirement is measured for the actual irrigation days of 72 which are the number subtracted the days of rainfall of 30 from the total irrigation days of 102. It is found that the irrigation water requirement for the uncontrol plot is 1,590mm as compared to 876mm(44.9% saved) for the 9cm-lined plot, 959mm(39.7% saved) for the 6cm-lined plot 1,010mm(36% saved) for the 3cm-lined plot and 1,082mm(32% saved) for the wheat straw lined plot. In the case of the Rotation irrigation method it is found that the water requirement for the plot irrigated at an interval of 8 days is 538mm(65% saved), as compared to 617mm(61.6% saved) for plot irrigated at an interval of 7 day 672mm(57.7% saved) for plot irrigated at an interval of 6day, 746mm(53.0% saved) for the plot irrigated at an interval of 5 days, 890mm 44.0% saved) for the plot irrigated at an interval of 4 days, and 975mm(38.6% saved) for the plot irrigated at an interval of 3 days. 7) The rate of evapotranspiration is found 2.8 around the end of month of July, as compared to 2.6 at the begining of August 3.4 around the end of August and 2.6 at the begining of August 3.4 around the end of August and 2.6 at the begining of September. 8) It is found that the saturation quantity of 30mm per day is decreased to 20mm per day though the use of vinyl covering. 9) The husking rate shows 75 per cent which is considered better.