بررسی تأثیر طول سرریز مستغرق بر تغییرات توپوگرافی بستر در خم 90 درجه‌ تند

نویسندگان

چکیده

در این پژوهش به بررسی اثر پارامتر هندسی طول سرریز مستغرق در قوس 90 درجه بر میزان آب‌شستگی اطراف آن و تغییرات توپوگرافی بستر پرداخته شده است. آزمایش‌ها در آزمایشگاه هیدرولیک دانشگاه شهید چمران اهواز در یک قوس 90 درجه با 2=R/B انجام شد. در این پژوهش با قراردادن 7 سرریز در ساحل خارجی قوس 90 درجه با ارتفاع 5 سانتی‌متر،‏ زاویه قرارگیری 30 درجه نسبت به خط عمود بر ساحل و با نسبت‌های 15‎/0،‏ 2‎/0 و 25‎/0 طول مستقیم سرریز به عرض فلوم،‏ که همه براساس معیارهای استاندارد محاسبه شده‌اند و در شرایط جریان ورودی 137‎/0،‏ 192‎/0 پایین‌تر از آستانه حرکت ذرات و شرایط جریان ورودی 247‎/0 و 3023‎/0 بالاتر از آستانه حرکت ذرات،‏ تغییرات بستر مورد بررسی قرار گرفت. نتایج بررسی‌ها نشان داد که کمترین حجم آب‌شستگی مربوط به سرریزی است که طول مستقیم آن 2‎/0 عرض فلوم است.

کلیدواژه‌ها


عنوان مقاله [English]

The effect of Bendway weir length on bed topography of a sharp 90 degree bend

نویسندگان [English]

  • h m
  • m sh
چکیده [English]

In this study, the effect of Bendway weir length on bed topography of a sharp 90 degree bend was investigated, experimentally. Tests are conducted at the hydraulic lab of Shahid-Chamran university in a 90 degree sharp bend (R/B=2). Seven Bendway weirs were placed at the outer bank with a height of 5 cm (one-third of flow depth), angel of 30 degrees and three different weir lengths (L/B= 0.15, 0.2 and 0.25), each under four different flow conditions (Froude number ranged from 0.137 to 0.3). At the end of each test, bed topography of bend were taken by a laser bed profiler and plotted by surfer. Comparison of scour and deposition patterns for different weir length shows that weir with the length to width ratio equal 0.2 provides the lowest volume of eroded bed material.
In this study, the effect of Bendway weir length on bed topography of a sharp 90 degree bend was investigated, experimentally. Tests are conducted at the hydraulic lab of Shahid-Chamran university in a 90 degree sharp bend (R/B=2). Seven Bendway weirs were placed at the outer bank with a height of 5 cm (one-third of flow depth), angel of 30 degrees and three different weir lengths (L/B= 0.15, 0.2 and 0.25), each under four different flow conditions (Froude number ranged from 0.137 to 0.3). At the end of each test, bed topography of bend were taken by a laser bed profiler and plotted by surfer. Comparison of scour and deposition patterns for different weir length shows that weir with the length to width ratio equal 0.2 provides the lowest volume of eroded bed material.
In this study, the effect of Bendway weir length on bed topography of a sharp 90 degree bend was investigated, experimentally. Tests are conducted at the hydraulic lab of Shahid-Chamran university in a 90 degree sharp bend (R/B=2). Seven Bendway weirs were placed at the outer bank with a height of 5 cm (one-third of flow depth), angel of 30 degrees and three different weir lengths (L/B= 0.15, 0.2 and 0.25), each under four different flow conditions (Froude number ranged from 0.137 to 0.3). At the end of each test, bed topography of bend were taken by a laser bed profiler and plotted by surfer. Comparison of scour and deposition patterns for different weir length shows that weir with the length to width ratio equal 0.2 provides the lowest volume of eroded bed material.
In this study, the effect of Bendway weir length on bed topography of a sharp 90 degree bend was investigated, experimentally. Tests are conducted at the hydraulic lab of Shahid-Chamran university in a 90 degree sharp bend (R/B=2). Seven Bendway weirs were placed at the outer bank with a height of 5 cm (one-third of flow depth), angel of 30 degrees and three different weir lengths (L/B= 0.15, 0.2 and 0.25), each under four different flow conditions (Froude number ranged from 0.137 to 0.3). At the end of each test, bed topography of bend were taken by a laser bed profiler and plotted by surfer. Comparison of scour and deposition patterns for different weir length shows that weir with the length to width ratio equal 0.2 provides the lowest volume of eroded bed material.
In this study, the effect of Bendway weir length on bed topography of a sharp 90 degree bend was investigated, experimentally. Tests are conducted at the hydraulic lab of Shahid-Chamran university in a 90 degree sharp bend (R/B=2). Seven Bendway weirs were placed at the outer bank with a height of 5 cm (one-third of flow depth), angel of 30 degrees and three different weir lengths (L/B= 0.15, 0.2 and 0.25), each under four different flow conditions (Froude number ranged from 0.137 to 0.3). At the end of each test, bed topography of bend were taken by a laser bed profiler and plotted by surfer. Comparison of scour and deposition patterns for different weir length shows that weir with the length to width ratio equal 0.2 provides the lowest volume of eroded bed material.
In this study, the effect of Bendway weir length on bed topography of a sharp 90 degree bend was investigated, experimentally. Tests are conducted at the hydraulic lab of Shahid-Chamran university in a 90 degree sharp bend (R/B=2). Seven Bendway weirs were placed at the outer bank with a height of 5 cm (one-third of flow depth), angel of 30 degrees and three different weir lengths (L/B= 0.15, 0.2 and 0.25), each under four different flow conditions (Froude number ranged from 0.137 to 0.3). At the end of each test, bed topography of bend were taken by a laser bed profiler and plotted by surfer. Comparison of scour and deposition patterns for different weir length shows that weir with the length to width ratio equal 0.2 provides the lowest volume of eroded bed material.

کلیدواژه‌ها [English]

  • Scoure-River.-Bendway weir length-Bed topography-?? degree bend-