مجله دفاع هوافضایی

بررسی تجربی اثر ارتفاع فینلت روی نوفه لبه فرار لایه مرزی آشفته

نوع مقاله : مقاله پژوهشی

نویسندگان

عباس افشاری 1
جابر رگنی لموکی 2

1 استادیار، دانشگاه علوم و فنون هوایی شهید ستاری، دانشکده مهندسی هوافضا، تهران، ایران

2 دانشجوی دکتری مهندسی هوافضا-آیرودینامیک/دانشگاه فردوسی مشهد، دانشکده مهندسی، گروه مکانیک

چکیده
در پژوهش حاضر، تأثیر ارتفاع فینلت‌ها به عنوان یک روش کنترل غیرفعال نوفه لبه‌فرار به صورت تجربی مورد بررسی قرار گرفته است. طیف فشار سطح، طول مشخصه نوسانات فشار سطح در راستای دهانه و سرعت جابجایی ساختارهای گردابه‌ای‌‌‌ در محدوده لبه‌فرار، پارامترهای مهمی در تعیین نوفه لبه‌فرار در دوردست هستند. به منظور اندازه‌گیری پارامترهای فوق، از یک صفحه تخت مجهز به حسگرهای اندازه‌گیری فشار ناپایای سطح، استفاده شده است. نتایج نشان داد که یک ناحیه با گرادیان فشار معکوس در پایین دست فینلت‌ها ایجاد شده و با افزایش ارتفاع تشدید می‌گردد. همچنین مشخص شد که ارتفاع فینلت به عنوان مقیاس طول، مقیاس مناسبی جهت نرمال کردن موقعیت طولی است. حضور تمامی فینلت‌های درشت منجر به کاهش قابل توجه طیف فشار سطح در تمامی محدوده فرکانسی شده و با افزایش ارتفاع، به میزان بیشتری کاهش می‌یابد. فینلت‌های ریز منجر به کاهش طیف فشار سطح در فرکانس‌های بالا و همزمان افزایش آن در فرکانس‌های پایین و میانی می‌گردند. استفاده از هر دو نوع فینلت‌ منجر به افزایش طول مشخصه در فرکانس‌های میانی و مخصوصاً پایین شده است. سرعت جابجایی ساختارهای گردابه‌ای نیز، در پایین‌دست تمامی فینلت‌های درشت و ریز، کاهش یافته و افزایش ارتفاع فینلت‌ها منجر به کاهش بیشتر آن می‌گردد.

کلیدواژه‌ها

فینلت
نوفه لبه فرار
طول مشخصه و سرعت جابجایی گردابه

موضوعات

عنوان مقاله English

Experimental investigation of the Effect of finlets height on Turbulent boundary layer Trailing-Edge Noise

نویسندگان English

Abbas Afshari 1
Jaber Ragani Lamouki 2
1 Department of Aerospace Engineering, Shahid Sattari Aeronautical University of Science and Technology, Tehran, Iran
2 P h.D student/Department of Mechanical Engineering, Ferdowsi University of Mashhad
چکیده English

This study experimentally investigates the effect of finlet height as a passive method for trailing edge noise control. The surface pressure spectra, spanwise length scale, and eddy convection velocity in the trailing edge region are key parameters governing far-field trailing edge noise. A flat plate instrumented with unsteady pressure sensors was employed to measure these parameters. Results indicated that a region with an inverse pressure gradient was created downstream of the finlets, and this effect intensified with an increase in height. It was also determined that the height of the finlet serves as an appropriate length scale for normalizing the longitudinal position. The presence of all coarse finlets significantly reduces the surface pressure spectra across the entire frequency range, and this reduction becomes more pronounced with increasing height. Fine finlets reduced high-frequency surface pressure spectra while increasing spectral levels at low-to-mid frequencies. The use of both types of finlets has led to an increase in the length scale at mid and particularly low frequencies. The eddy convection velocity has also decreased downstream of all the coarse and fine finlets, and an increase in the height of the finlets results in a further reduction in this velocity.

کلیدواژه‌ها English

Finlet
Trailing Edge Noise
length scale
Eddy Convection Velocity
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مجله دفاع هوافضایی
دوره 3، شماره 3
پاییز 1403
صفحه 90-115

  • تاریخ دریافت 27 مرداد 1403
  • تاریخ بازنگری 06 آبان 1404
  • تاریخ پذیرش 21 آذر 1403

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