کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4993213 1457613 2017 17 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Upstream roughness and Reynolds number effects on turbulent flow structure over forward facing step
ترجمه فارسی عنوان
زلزله بالادست و تعداد رینولدز بر ساختار جریان آشفته در مرحله رو به جلو تاثیر می گذارد
کلمات کلیدی
جریان جدا و مجدد گام رو به جلو، زبری دیوار، تجزیه و تحلیل چهارگانه، همبستگی دو نقطه،
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
چکیده انگلیسی
This paper presents results of experiments conducted to investigate the effects of Reynolds number and upstream wall roughness on the turbulence structure in the recirculation and recovery regions of a smooth forward facing step. A reference smooth upstream wall and a rough upstream wall made from sand gains were studied. For the smooth upstream wall, experiments were conducted at Reynolds number based on the freestream velocity and step height (h), Reh = 4940, 8400 and 8650. The rough wall experiments was performed at Reh = 5100, 8200 and 8600 to closely match the corresponding Reh experiment over the smooth wall. The reattachment lengths in the smooth wall experiments were Lr/h ≈ 2.2, but upstream roughness significantly reduced these values to Lr/h ≈ 1.3. The integral scales within the recirculation bubbles were independent of upstream roughness and Reynolds number; however, upstream roughness significantly increased the spatial coherence and integral scales outside the recirculation bubbles and in the recovery region. Irrespective of the upstream wall condition, the redeveloping boundary layer recovered at 25h from reattachment.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Fluid Flow - Volume 66, August 2017, Pages 226-242
نویسندگان
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