بررسی تجربی عملکرد فینلت‌های کاهش‌دهنده نویز لبه‌فرار

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار/دانشکده مهندسی هوافضا/ دانشگاه علوم و فنون هوایی شهید ستاری

2 هیات علمی-دانشگاه یزد

3 دانشکده مهندسی هوافضا، دانشگاه علوم و فنون هوایی شهید ستاری

چکیده

در مطالعه حاضر، کارایی فینلت به عنوان یک روش کنترل غیرفعال نویز لبه‌فرار به صورت تجربی مورد بررسی قرار گرفته است. طیف فشار سطح، طول مشخصه نوسانات فشار سطح در راستای دهانه بال و سرعت جابجایی ساختارهای گردابه‌ای‌‌‌ در محدوده لبه‌فرار پارامترهای مهمی در تعیین نویز لبه‌فرار در دوردست هستند. در این مطالعه جهت اندازه‌گیری پارامترهای فوق، یک صفحه تخت مجهز به سنسورهای اندازه‌گیری فشار ناپایای سطح، طراحی و ساخته شده است. استفاده از فینلت‌ها با فواصل عرضی زیاد، منجر به کاهش طیف فشار سطح در فرکانس‌های میانی و بالا و افزایش طول مشخصه در راستای دهانه مدل در فرکانس‌های پایین و میانی شده است. از طرف دیگر، برای فینلت‌ها با فواصل عرضی کم، در حالی که طیف فشار سطح در فرکانس‌های بالا به مقدار بیشتری کاهش یافته، افزایش نامطلوبی در فرکانس‌های پایین تا میانی بوجود آمده است. فینلت‌های ریز می‌توانند منجر به کاهش همدوسی عرضی در فرکانس‌‌های میانی و بالایی گردند. سرعت جابجایی ساختارهای گردابه‌ای نیز در پایین دست همه فینلت‌‌ها کاهش یافته است. در نهایت با استفاده از مدل تحلیلی امیت-راجر، تغییرات نویز لبه‌فرار در دوردست ناشی از حضور فینلت‌های مختلف پیش بینی شده که نتایج نشان‌دهنده کارایی مناسب فینلت‌ها در محدوده فرکانس‌های میانی و بخصوص بالاست.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental Investigation of the Performance of Trailing Edge Noise-Reducing Finlets

نویسندگان [English]

  • abbas afshari 1
  • Ali Akbar Dehghan 2
  • Ali Negahban.B 3
  • Ahmadreza Ayoobi 3
1 Assistant Professor, Department of Aerospace Engineering, Shahid Sattari Aeronautical University of Science and Technology, Iran
2 Mech. Eng. Dept, Faculty of Engineering, Yazd University, IRAN
3 Department of Aerospace Engineering, Shahid Sattari Aeronautical University of Science and Technology
چکیده [English]

In the present study, the efficiency of the finlet as a means of passive trailing-edge noise control has been experimentally investigated. Surface pressure spectra, spanwise length scale, and eddy convection velocity in the trailing-edge region are important parameters in determining far-field trailing-edge noise. In the present study to measure the above parameters, a flat-plate model equipped with unsteady surface pressure transducers has been designed and built. Results have shown that the flow behavior downstream of the finlets is strongly affected by the spacing between the finlets. The use of finlets with coarse spacing leads to a reduction in the surface pressure spectrum at mid to high frequencies and an increase in the spanwise length scale at low to mid frequencies. On the other hand, for the finlets with fine spacing, while the surface pressure spectrum has been further reduced at high frequencies, there has been an undesirable increase at low to mid frequencies. Moreover, fine finlets can significantly reduce the coherence and eddy convection velocity at mid to high frequencies. Finally, the Amiet-Roger model has been used to evaluate the changes in far-field trailing-edge noise and the results have shown the effectiveness of finlets in the mid and especially high frequency range.

کلیدواژه‌ها [English]

  • Finlet
  • trailing-edge noise
  • Turbulent boundary layer
  • Surface pressure spectra
  • Eddy
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