Explicit normal water depth formulae and optimal economical section of the triangular channel

2016 ◽  
pp. 989-992
Author(s):  
H Gu ◽  
Y Han ◽  
T Peng ◽  
Y Gao
Keyword(s):  
Water Depth ◽  
Triangular Channel ◽  
Normal Water

The Direct Solution on Normal Depth of an Egg-Shaped Section Tunnel

2014 ◽  
Vol 580-583 ◽  
pp. 1901-1905
Author(s):  
Hui Wen
Keyword(s):  
Water Depth ◽  
Hydraulic Calculation ◽  
Average Error ◽  
Maximum Relative Error ◽  
Calculation Formula ◽  
Circular Arc ◽  
Minimum Residual ◽  
Normal Water ◽  
Computation Error ◽  
Shaped Section

An egg-shaped is consisted of four parts: One arc bottom, two side circular arc arch and one circular arc roof umbrella arch. It is complex shape. Aiming at traditional methods there are complicated and the defects of inaccurate. on the basis of summarizing the predecessors' research, Based on the normal water depth basic equation mathematical transformation of egg-shaped sections, the interrelation between dimensionless water depth and the dimensionless parameter were analyzed, We use the power function as the formula form, with minimum residual standard deviation as the goal, the coefficients of the formula can be calculated based on the theory of optimization and regression. Then, we get calculation formula for normal water depth. This formula is not a piecewise function, and need not to choose the suitable formula according to the dividing flow. The results can be directly calculated. Results of the example calculation and error analysis showed that the maximum relative error of normal water depth was 0.675% respectively in the utility range (The ratio of water depth divided by height of tunnel is from 0.05 to 0.85). Using this algorithm, above 92 % of the computation error on normal water depth was less than 0.25%. The average error of the formulas was not more than 0.118% .The hydraulic calculation formula will be widely used in engineering design and project management due to its high accuracy and simple form.

A New Algorithm for Normal Water Depth of the Ordinary Arched Tunnel

2011 ◽  
Vol 250-253 ◽  
pp. 2902-2905
Author(s):  
Hui Wen ◽  
Feng Ling Li
Keyword(s):  
Water Depth ◽  
Maximum Error ◽  
Transcendental Equation ◽  
Structure Design ◽  
Linear Solution ◽  
Relationship Analysis ◽  
Calculation Step ◽  
Normal Water ◽  
New Formula ◽  
The Relationship

Arched section consisted of a rectangle and a semicircle part. It is commonly applied in the field of hydroelectric engineering. The normal water depth computation equation for an arched tunnel is a transcendental equation and no analytic solution. In this paper, based on the mathematics transformation for the basis equation and the relationship analysis between the dimensionless normal water depth and the relative parameters, a new linear solution formula are established for the calculation of normal water depth for arched section tunnel according to the fitting principle. This method overcomes the shortage of other iterative trial calculating methods, such as complex calculation step, depend on the special chart and curve, and existed serious error. The new formula is simply and the maximum error is less than 0.6156% under the general engineering design range (ratio of normal water depth and arch radius is between 1 to 1.5416). it can be used on the engineering designing practice and the edit of the handbook of hydraulic structure design.

scholarly journals New and improved three and one-third parabolic channel and most efficient hydraulic section

2017 ◽  
Vol 44 (5) ◽  
pp. 387-391 ◽  
Author(s):  
Yan-Cheng Han ◽  
Said M. Easa
Keyword(s):  
Exact Solution ◽  
Cross Section ◽  
Water Depth ◽  
Open Channel ◽  
Hydraulic Characteristics ◽  
Explicit Formulas ◽  
Practical Applications ◽  
Normal Water ◽  
Wetted Perimeter ◽  
Approximate Formulas

Several parabolic-shaped open channel sections are available in the literature, including quadratic and semi-cubic parabolic sections. This paper presents a three and one-third parabolic cross-section that has superior characteristics compared to those of previous parabolic-shaped sections. The section characteristics, including two approximate formulas for the wetted perimeter and a simple iterative formula for the normal water depth are presented. The exact solution for the most efficient hydraulic section is derived. The results show the width–depth ratio for the most efficient hydraulic section is 2.1273. Practical applications of the proposed most efficient hydraulic section are presented, including direct formulas for the discharge and explicit formulas of normal and critical depths. The results show that the proposed section improves the hydraulic characteristics compared with other parabolic sections and trapezoidal section.

Vegetation changes in shallow marsh wetlands under improving moisture regime

1973 ◽  
Vol 51 (8) ◽  
pp. 1443-1457 ◽  
Author(s):  
J. B. Millar
Keyword(s):  
Species Composition ◽  
Water Depth ◽  
Plant Cover ◽  
Open Water ◽  
Growing Season ◽  
Vegetation Changes ◽  
Moisture Regime ◽  
Complete Elimination ◽  
Normal Water ◽  
Emergent Species

Changes in species composition and plant cover were studied in relation to moisture regime over a 10-year period in 71 shallow marsh wetlands in the grassland and parkland regions of Saskatchewan. Decreases in density of the shallow marsh emergents Polygonum coccineum, Carex atherodes, Scolochloa festucacea, and Eleocliaris palustris occurred with greater-than-normal water depth at the start of the growing season but 2 or more years of continuous flooding were required to eliminate emergent cover completely and convert the wetland to open water. Repeated autumn reflooding also resulted in complete elimination of emergent species. Changes in species composition occurred when basins were grazed and as vegetation reestablished after cultivation but no changes followed mowing or burning. Alopecurus aequalis, Beckmannia syzigachne, Glyceria grandis, and G. pulchella are designated as "disturbance" species on the basis of their response to soil-exposing events. Presence of small amounts of deep marsh emergents in shallow marsh wetlands is not considered a reliable indicator of wetter moisture regime. Species composition of rooted submergents in a wetland can be used as an indicator of its moisture regime. Shallow marsh wetlands in basins of 1 ac (0.41 ha) or less experienced little year-long flooding and converted to open water only under atypical conditions. Larger wetlands required basin depths in excess of 36 in. (96.4 cm) to have any amount of year-long flooding and to convert to open water. These basin size and depth criteria have applications in habitat evaluation by waterfowl managers.

Simplified Calculation Method of Normal Water Depth on II Type Horseshoe Tunnel with Flat-Bottom

2013 ◽  
Vol 353-356 ◽  
pp. 1353-1358
Author(s):  
Hui Wen ◽  
Feng Ling Li
Keyword(s):  
Cross Section ◽  
Water Depth ◽  
Maximum Error ◽  
Transcendental Equation ◽  
Structure Design ◽  
Flat Bottom ◽  
Relationship Analysis ◽  
Calculation Step ◽  
Normal Water ◽  
Simplified Calculation

Abstract: II type horseshoe with flat–bottom evolved from standard II type horseshoe cross-section. It is composed of a flat-bottom and three arc sections. It is commonly applied in the field of hydroelectric engineering. The normal water depth computation equation for II type horseshoe cross-section with flat–bottom tunnel is a transcendental equation and no analytic solution. In this paper, based on the mathematics transformation for the basis equation and the relationship analysis between the dimensionless normal water depth and the relative parameters, a simplified calculation formula is established for the calculation of normal water depth for II type horseshoe cross-section with flat–bottom tunnel according to the fitting principle. This method overcomes the shortage of other iterative trial calculating methods, such as complex calculation step, depend on the special chart and curve, and existed serious error. The formula is simply and the maximum error is less than 0.23% under the general engineering design range (ratio of normal water depth and arch radius is between 0.05 - 1.45). it can be used on the engineering designing practice and the edit of the handbook of hydraulic structure design.

The Direct Solution on Normal Water Depth of I Type Horseshoe Tunnel with Flat–Bottom

2012 ◽  
Vol 170-173 ◽  
pp. 1595-1600
Author(s):  
Hui Wen ◽  
Feng Ling Li
Keyword(s):  
Cross Section ◽  
Water Depth ◽  
Maximum Error ◽  
Transcendental Equation ◽  
Structure Design ◽  
Direct Solution ◽  
Flat Bottom ◽  
Relationship Analysis ◽  
Calculation Step ◽  
Normal Water

Abstract: I type horseshoe with flat–bottom evolved from standard I type horseshoe cross-section. It is composed of a flat-bottom and three arc sections. It is commonly applied in the field of hydroelectric engineering. The normal water depth computation equation for I type horseshoe cross-section with flat–bottom tunnel is a transcendental equation and no analytic solution. In this paper, based on the mathematics transformation for the basis equation and the relationship analysis between the dimensionless normal water depth and the relative parameters, a direct solution is established for the calculation of normal water depth for I type horseshoe cross-section with flat–bottom tunnel according to the fitting principle. This method overcomes the shortage of other iterative trial calculating methods, such as complex calculation step, depend on the special chart and curve, and existed serious error. The formula is simply and the maximum error is less than 0.3% under the general engineering design range (ratio of normal water depth and arch radius is between 0 to 1.4471). it can be used on the engineering designing practice and the edit of the handbook of hydraulic structure design.

Comparison of the performance of oscillating water column devices based on arrangements of water columns

2020 ◽  
Vol 14 (3) ◽  
pp. 7082-7093
Author(s):  
Jahirwan Ut Jasron ◽  
Sudjito Soeparmani ◽  
Lilis Yuliati ◽  
Djarot B. Darmadi
Keyword(s):  
Wave Propagation ◽  
Water Column ◽  
Water Depth ◽  
Graphical Form ◽  
Wave Power ◽  
Oscillating Water Column ◽  
Power Absorption ◽  
Water Columns ◽  
Single Column ◽  
Parallel Arrangement

The hydrodynamic performance of oscillating water column (OWC) depends on the depth of the water, the size of the water column and its arrangement, which affects the oscillation of the water surface in the column. An experimental method was conducted by testing 4 water depths with wave periods of 1-3 s. All data recorded by the sensor is then processed and presented in graphical form. The research focused on analyzing the difference in wave power absorption capabilities of the three geometric types of OWC based on arrangements of water columns. The OWC devices designed as single water column, the double water column in a series arrangement which was perpendicular to the direction of wave propagation, and double water column in which the arrangement of columns was parallel to the direction of wave propagation. This paper discussed several factors affecting the amount of power absorbed by the device. The factors are the ratio of water depth in its relation to wavelength (kh) and the inlet openings ratio (c/h) of the devices. The test results show that if the water depth increases in the range of kh 0.7 to 0.9, then the performance of the double chamber oscillating water column (DCOWC) device is better than the single chamber oscillating water column (SCOWC) device with maximum efficiency for the parallel arrangement 22,4%, series arrangement 20.8% and single column 20.7%. However, when referring to c/h, the maximum energy absorption efficiency for a single column is 27.7%, double column series arrangement is 23.2%, and double column parallel arrangement is 29.5%. Based on the results of the analysis, DCOWC devices in parallel arrangement showed the ability to absorb better wave power in a broader range of wave frequencies. The best wave of power absorption in the three testing models occurred in the wave period T = 1.3 seconds.

Sign in / Sign up

Export Citation Format

Share Document