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RISS 인기검색어
- 검색키워드
- 저자 : Ali R. Vatankhah (검색결과 3 건)
- 무료
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Limiting Dimensions for Trapezoidal Channels and Control Notches (Design Aid)
Ali R. Vatankhah 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.4
Determining the channel dimensions leading to critical flow conditions for given values of specific energy or specific force plays an important role in channel transition design. A closed-form analytical solution for the problem can only be derived for triangular,rectangular and parabolic channels. This is not possible, however, for other practical geometries, such as trapezoidal channels. The dimensions of the trapezoidal control notch are determined by simultaneously satisfying the critical state of flow and specific energy equation. At present, graphical solutions are used for design discharges less than 2.83 m3/s. In current study, direct solutions to compute the limiting dimensions of the trapezoidal channel and direct solutions to design of the trapezoidal control notch are derived. The proposed solutions are nearly exact and will be useful in the design and analysis of the trapezoidal channels and notches.
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Ali R. Vatankhah 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.1
An accurate solution method is essential to the calibration of the nonlinear Muskingum model. Most of the earlier researchers haveused inaccurate Euler’s solution method which is manipulated to get a better fit for observed Wilson’s data (1974). Euler’s methodwhich is adopted by most previous researchers is not very accurate and results in unsuitable simulation based on the nonlinearMuskingum model as shown in this discussion. This study proposes fourth-order Runge-Kutta method as a suitable and accuratesolution method for simulation stage. When more accuracy is needed, the structure of the Muskingum model can be modified toproduce more degree of freedom in model calibration procedure. For this purpose, a new five-parameter nonlinear Muskingummodel is proposed. The proposed model is easy to formulate and use. The results show that the improvement in the fit of the proposednonlinear Muskingum model is substantial.
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New Open Channel with Elliptic Sides and Horizontal Bottom
Said M. Easa,Ali R. Vatankhah 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.4
This paper presents a new general open channel section with elliptic sides and horizontal bottom. The proposed section producesspecial channel forms, such as a circular section with a horizontal bottom, a circular section, and a rectangular section. Exact andapproximate formulas for the area and perimeter of the channel are derived. These formulas are then used to develop an optimizationmodel for determining the optimal section design that minimizes the total construction cost for excavation and composite linings. Inaddition, the most hydraulically efficient elliptic section was derived. The constraints of the optimization model include channeldischarge and physical requirements, such as flow depth, top width, and side slope with fixed or depth-dependent freeboard. The costperformance of the proposed section was compared with another general open channel section (power-law) and the trapezoidalsection using different design scenarios. The results show that the new section is substantially more economical and more flexiblethan the existing power-law section, and is generally superior to the trapezoidal section.
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