کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7176077 | 1466597 | 2014 | 17 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Effect of flow regime change from subsonic to transonic on the air loads of an oscillating airfoil
ترجمه فارسی عنوان
اثر تغییر رژیم جریان از ذره ای به ترانسونیک بر روی بارهای هوا یک هواپیما نوسان تغییر می کند
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کلمات کلیدی
جریان زیرسیستم جریان تراونیکی، تناوبی، ضریب لیفت، ضریب لحظه تکان دادن، تعادل هارمونیک،
موضوعات مرتبط
مهندسی و علوم پایه
سایر رشته های مهندسی
مهندسی مکانیک
چکیده انگلیسی
In this research, the effect of flow regime change from subsonic to transonic on the air loads of a pitching NACA0012 airfoil is investigated. To do this, the effect of change in flow regime on the lift and pitching moment coefficients hysteresis cycles is studied. The harmonic balance approach is utilized for numerical calculation due to its low computational time. Verifications are also made with previous works and good agreements are observed. The assessment of flow regime change on the aforementioned hysteresis cycles is accomplished in the Mach number range of M=0.65-0.755. The reduced frequency and pitch amplitude also vary from k=0.03 to 0.1 and α0=1-2.51°, respectively. Results show that the effect of increase in Mach number is to increase and decrease the lift coefficient during downstroke and upstroke, respectively, whereas at low reduced frequencies, the effect of increase in Mach number may lead to a reverse manner when airfoil moves toward its extremum angle of attack. Results also reveal that as the pitch amplitude varies, the shape of lift coefficient hysteresis cycle depends more on the pitch amplitude than on the appearance of shock. It is shown that as the Mach number increases, the incidence angles correspond to the extremum pitching moment, and depending on the reduced frequency, lie between zero and extremum angle of attack. These incidence angles shift toward the extremum angle of attack as the reduced frequency decreases. Results also show that the increase in pitch amplitude at low Mach number, in such a way that leads to the formation of shock around the extremum angle of attack, causes the extremum pitching moment to appear around these angles and at high Mach number, depending on the reduced frequency, the extremum pitching moment incidence angles would be between zero and extremum incidence angle.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Fluids and Structures - Volume 50, October 2014, Pages 312-328
Journal: Journal of Fluids and Structures - Volume 50, October 2014, Pages 312-328
نویسندگان
Masoud Kharati Koopaee,