بررسی آزمایشگاهی تأثیر شیب مثبت صفحات مشبک افقی بر روی مشخصات هیدرولیکی شیب‌شکن قائم

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه مراغه، مراغه، ایران

2 گروه مهندسی عمران، دانشکده فنی مهندسی، مراغه، مراغه، ایران

3 گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه مراغه،مراغه،ایران

4 دانشجوی کارشناسی ارشد عمران آب و سازه های هیدرولیکی، گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه مراغه، مراغه، ایران

چکیده

در تحقیق حاضر، 105 آزمایش با هدف بررسی تأثیر شیب صفحات مشبک افقی بر روی مشخصات هیدرولیکی شیب­شکن قائم با جریان زیربحرانی در بالادست انجام شد. آزمایش­ها در دو مدل شیب­شکن قائم ساده و شیب­شکن قائم مجهز به صفحات مشبک افقی و شیبدار (سه شیب) با دو نسبت تخلخل تنظیم شد. بازه عمق بحرانی نسبی از 07/0 تا 24/0 بوده و شیب صفحات مشبک افقی ◦7، ◦14 و ◦21 و نسبت تخلخل صفحات مشبک برابر با دو مقدار 40 و 50 درصد درنظر گرفته شد. پارامترهای طول نسبی خیس­شده، طول نسبی تلاطم، عمق نسبی استخر، عمق نسبی پایین­دست و انرژی باقی­مانده نسبی مورد بررسی قرار گرفت. در تمامی حالات مورد بررسی با افزایش عمق بحرانی نسبی، پارامترهای طول نسبی تلاطم، عمق نسبی استخر، عمق نسبی پایین­دست و انرژی باقی­مانده نسبی افزایش می­یابند. نتایج نشان داد که با افزایش شیب صفحات مشبک، پارامترهای طول نسبی خیس­شده، طول نسبی تلاطم و عمق نسبی استخر افزایش می­یابند. این در حالی است که شیب صفحات مشبک تأثیر چندانی بر روی عمق نسبی پایین­دست و انرژی باقی­مانده نسبی ندارد. همچنین مشاهده گردید که افزایش تخلخل صفحات مشبک باعث کاهش پارامترهای طول نسبی خیس شده، طول نسبی تلاطم و عمق نسبی استخر و افزایش عمق نسبی پایین­دست می­گردد. این در حالی است که تخلخل صفحات مشبک بر روی انرژی باقی­مانده نسبی بی‌تأثیر است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Experimental Investigation of the Effect of Positive Slope of the Horizontal Screen on Hydraulic Characteristics of Vertical Drop

نویسندگان [English]

  • Rasoul Daneshfaraz 1
  • vadoud hasanniya 2
  • Reza Mirzaei 3
  • Ali Bazyar 4
1 Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran.
2 Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.
3 Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.
4 Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran.
چکیده [English]

In the present study, 105 tests were carried out to investigate the effect of horizontal screen slope on hydraulic characteristics of vertical drop with the subcritical flow in upstream. The experiments were arranged in two models, plain vertical drop and vertical drop equipped with horizontal and sloping (three slopes) screens in two porosity ratios. The range of relative critical depth was from 0.07 to 0.24 the screen slopes were 7◦, 14◦, 21◦, and the screen porosities  were considered to be 40% and 50%. The relative wetted length of the screen, the relative turbulance length, the relative depth of pool, the relative downstream depth, and the relative residual energy were analyzed. In all cases, by increasing the relative critical depth, the turbulance length, pool depth, downstream depth, and relative residual energy were increased. The results showed by increasing the slope of  screen, the characteristics of the relative wetted length of the horizontal screen, relative turbulance length, and relative pool depth increases. However, the slope of screen has no effect on the relative downstream depth and the relative residual energy. It was also observed that with increasing porosity ratio of the screen, the characteristics of the relative wetted length of the horizontal screen, relative turbulance length, and relative pool depth decreases, and the relative downstream depth increases. But the porosity of screens has an insignificant effect on the relative residual energy.

کلیدواژه‌ها [English]

  • Porosity
  • relative residual energy
  • slope of the horizontal screen
  • vertical drop

مراجع

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تحقیقات آب و خاک ایران
دوره 50، شماره 10
اسفند 1398
صفحه 2499-2509

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