مطالعه تجربی و عددی اثر صدمه ستاره‌‌ای شکل بر عملکرد آیرودینامیکی بال یک پهپاد

نوع مقاله : مقاله پژوهشی

نویسندگان

1 پژوهشگاه هوافضا ،وزارت علوم، تحقیقات و فناوری، تهران، ایران

2 دانشکده مهندسی هوافضا، دانشگاه صنعتی امیرکبیر، تهران، ایران

چکیده

این مقاله عملکرد آیرودینامیکی بال یک پهپاد را که توسط برخورد یک جسم مانند گلوله جنگی دچار صدمه شده است، با دو روش شبیه‌سازی عددی و تجربی مورد مطالعه قرار می‌دهد. به منظور شبیه‌سازی اثر برخورد گلوله و ایجاد گوشه‌های تیز در صدمه واقعی، از یک حفره ستاره‌ای شکل برای شبیه‌سازی صدمه استفاده شده است. مقطع بال مورد مطالعه، ایرفویل‌ نامتقارن با شمارة NACA 641-412 در نظر گرفته شده است. در این تحقیق، اثر موقعیت صدمه در راستای دهانه بال در سه مکان مختلف سر، میانه و ریشه بال بر روی عملکرد آیرودینامیکی بال تحت زوایای حمله مختلف مطالعه شده است. در بخش تجربی این مقاله مشخصات جریان عبوری از روی بال و صدمه، با تکنیک رنگ استاندارد آشکارسازی شده و اثرات آن بر ضرایب آیرودینامیکی ارائه شده است. به منظور بررسی قابلیت حل عددی در پیش‌بینی عملکرد آیرودینامیکی بال صدمه‌دیده، جریان اطراف بال به صورت عددی تحلیل شده و نتایج حاصل با نتایج آزمایشگاهی اعتبارسنجی و مقایسه شده است. در نتایج آشکارسازی جریان، یک جریان جت قوی و دو گردابه با چرخش خلاف جهت، متصل به صدمه ستاره‌ای شکل، در سطح مکش بال مشاهده می‌شود. نتایج نشان می‌دهد صدمه ستاره‌ای که مساحت آن حدود 1 درصد مساحت کل بال است می‌تواند ضریب برآی بال را حدود 6 درصد در مقایسه با بال سالم کاهش و ضریب پسا را حدود 7/15 درصد نسبت به بال سالم، افزایش دهد. همچنین صدمه باعث می‌شود بال ضریب ممان‌پیچشی منفی‌تری را تجربه کند. نتایج صدمه در مکان‌های مختلف نشان داد که صدمه در نزدیک نوک بال تأثیر کمتری بر کاهش کارایی آیرودینامیکی بال دارد.

ضریب پسا را حدود 7/15 درصد نسبت به بال سالم، افزایش دهد. همچنین صدمه باعث می‌شود بال ضریب ممان‌پیچشی منفی‌تری را تجربه کند. نتایج صدمه در مکان‌های مختلف نشان داد که صدمه در نزدیک نوک بال تأثیر کمتری بر کاهش کارایی آیرودینامیکی بال دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental and Numerical Investigation of Aerodynamic Performance of a Star-Shaped Damaged Wing

نویسندگان [English]

  • S. Abdolahi 1
  • M. Mani 2
1 Aerospace Research Institute, Ministry of Science, Research and Technology, Tehran, Iran
2 Aerospace Engineering Department, Amirkabir University of Technology, Tehran, Iran
چکیده [English]

In this paper the flow on a finite wing with star damage is numerically and experimentally investigated to understand the influences of damage on the aerodynamic characteristics of wing. To study the effects of different span positions, the damage was considered in tip, middle and root position of the wing span. The wing model of studies is a section of NACA 641-412 asymmetric airfoil with 200mm chord and 800mm span. The aerodynamic coefficients and their increments due to damage were extracted and the results were compared to each other and also to the experimental results. The flow visualization of flow over the damaged wing has been done with pain technique to make evident the flow structure on the model and to understand the influences of damage on the flow. For better understanding of the ability of numerical modeling prediction of aerodynamic performance of a damaged wing, the flow around the wing was numerically analyzed and was validated with the experimental results. A star damage with area about 1% of the wing, can decrease the lift coefficient about 6% and increase the drag coefficient about 15.7% compared with undamaged wing. The star damaged wing also experiences more negative pitching moment coefficient. The results of damage in different locations showed that the damage near to wing tip has less impact on decrement of aerodynamic efficiency.

For better understanding of the ability of numerical modeling prediction of aerodynamic performance of a damaged wing, the flow around the wing was numerically analyzed and was validated with the experimental results. A star damage with area about 1% of the wing, can decrease the lift coefficient about 6% and increase the drag coefficient about 15.7% compared with undamaged wing. The star damaged wing also experiences more negative pitching moment coefficient. The results of damage in different locations showed that the damage near to wing tip has less impact on decrement of aerodynamic efficiency.

کلیدواژه‌ها [English]

  • Star-shaped damaged wing
  • Aerodynamic characteristics
  • Wind tunnel tests
  • Flow visualization
  • Numerical modeling
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