پژوهش حاضر به‌منظور ارزیابی این مدل، به‌صورت کرت‌های خردشده در قالب بلوک کامل تصادفی بر روی رقم هاشمی با سه تکرار در دو سال زراعی انجام شد. عامل اصلی آزمایش شامل آبیاری در 2 سطح (غرقاب، آبیاری نوبتی 10 روز) و عامل فرعی نیتروژن در 3 سطح (شاهد، 50 و 100 کیلوگرم در هکتار) More
پژوهش حاضر به‌منظور ارزیابی این مدل، به‌صورت کرت‌های خردشده در قالب بلوک کامل تصادفی بر روی رقم هاشمی با سه تکرار در دو سال زراعی انجام شد. عامل اصلی آزمایش شامل آبیاری در 2 سطح (غرقاب، آبیاری نوبتی 10 روز) و عامل فرعی نیتروژن در 3 سطح (شاهد، 50 و 100 کیلوگرم در هکتار) بود. ارزیابی مقادیر شبیه‌سازی و اندازه‌گیری شده عملکرد دانه، بیولوژیک، نیتروژن دانه و کل با استفاده از پارامترهای ضریب تبیین، آزمون t، RMSE و RMSEn انجام گرفت. نتایج نشان داد مقدار ریشه میانگین مربعات خطای نرمال شده بین 8 تا 13 درصد، شبیه‌سازی مقادیر ماده خشک و نیتروژن جذب‌شده در شرایط آبیاری و کود نیتروژن متغیر است. عملکرد با ریشه میانگین مربعات خطای 254 تا 261 کیلوگرم در هکتار و ریشه میانگین مربعات خطای نرمال شده 8 تا 9 درصد شبیه‌سازی شد. مقادیر ضریب تبیین برای عملکرد دانه، عملکرد بیولوژیک، نیتروژن دانه و نیتروژن کل به ترتیب برابر با 85/0، 91/0، 79/0 و 84/0 بود. مدل مقدار نیتروژن دانه و کل را بیشتر از مقدار اندازه‌گیری، شبیه‌سازی نمود. نتایج تحقیق نشان داد که می‌توان از مدل ORYZA2000 برای پشتیبانی نتایج پژوهش‌های تحت شرایط محدودیت آبیاری و نیتروژن استفاده کرد.
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A large number of river engineering projects, e.g. design of flood-control discharges, realignment of river channels, bank protection and sediment transport, requires accurate estimation of discharge in the compound channels such as rivers. Shiono-Knight method (SKM) is More
A large number of river engineering projects, e.g. design of flood-control discharges, realignment of river channels, bank protection and sediment transport, requires accurate estimation of discharge in the compound channels such as rivers. Shiono-Knight method (SKM) is known as a capable tool to modeling discharge in prismatic compound channels. This research used the SKM, which is based on solving two-dimensional equations for flows in open channel by averaging the Navier-Stokes equations. Firstly, the values of depth-averaged velocities and discharge were calculated, then those compared with measurement data in 92-93 time period. Finally, the relation between depth and discharge flow have been stablished for 92-93 time period. The results of predicted depth-averaged velocity and discharge obtained from SKM compared with measured values indicate that SKM can accurately predict the velocity distributions if the two coefficients of friction factor and Roaring manning are chosen based on accurate patterns. The results of model shows to be not good agreement with experimental data. The discharge and depth-averaged velocity were estimated with 3.8 and 12.5 percent error.
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In this research, using two hydrological methods, convex and At-Kin, the flood routing was investigated in the Sarqanat and Kalel reach located in the Dalki River. To perform this operation, 26 flood hydrographs were selected as input to the model. and the output hydrog More
In this research, using two hydrological methods, convex and At-Kin, the flood routing was investigated in the Sarqanat and Kalel reach located in the Dalki River. To perform this operation, 26 flood hydrographs were selected as input to the model. and the output hydrographs of the models were compared to the observed output hydrograph at the station located in downstream of reach. In order to evaluate the efficiency and accuracy of the models, the RMSE was used. The results showed that the hydrological method of Atkin is significantly less accurate than the graphic (regression) method of Convex, but it is more accurate compared to the two sub-methods of Singh and SCS of Convex. Also it was found that the graphical method of Convex (or regression) with an average error value of 21.26 m3/s. is more suitable than other methods in this research. And then the best methods include Atkin, Singh and SCS with RMSE values of 70.16, 77.87 and 79.3 m3/s. However, the difference between Singh and SCS methods is not serious. The RMSE values in all methods used in this research show a lower value in 50% Qp compared to the Qp. In Atkin's method, the amount of error in the conditions of using 50%Qp has reached from 78.5 to 70.71 m3/s. According to the mentioned results, it is recommended that researchers use 50%Qp in flood routing operation.
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