השפעת גמישות שפת זרימה על החתימה האקוסטית של כנף בזרימה לא-תמידית

ולדימיר כץ
עבודה לקראת תואר מגיסטר תחת הנחייתו של פרופ"מ א. מנלה
הפקולטה להנדסת אוירונוטיקה וחלל
טכניון - המכון הטכנולוגי לישראל

Trailing edge noise is identified as a major component of airframe noise, particularly during airplanes approach for landing, when extensive use is made of high-lift devices. Consequently, significant efforts have been made to analyze the acoustic signature of such devices, in various setups and flight conditions. Common to almost all of these works is a consideration of a rigid lift device, in which the impacts of element geometry and orientation are examined.

The objective of the present work is to apply existing vibroacoustic methodologies to examine the effect of trailing edge elasticity on the acoustic radiation of an otherwise rigid airfoil. We consider the far-field radiation of a thin airfoil attached to a flexible downstream appendage, and compare it with radiation by a counterpart rigid structure. Flow unsteadiness is modeled as an incident line vortex, convected by the mean flow in the vicinity of the airfoil.

Assuming low-Mach high-Reynolds flight conditions, the near-field flow is examined based on thin-airfoil theory, and the far-field sound is computed using a compact-body acoustic analogy. Results describe the impact of trailing edge elasticity on near- and far-field flow characteristics, and indicate on the amplifying  effect of edge flexibility on the far-field sound. In particular, far-field radiation in the non-rigid case is affected by stronger edge-point interactions with incoming vorticity, as well as by long-time flow-induced oscillations at the system least stable eigenfrequency.

הסמינר יינתן בעברית

רביעי, 15-04-2015, 16:30 (התכנסות בשעה 16:00)

כיתת הספריה, חדר 165, קומה ראשונה

כיבוד קל יוגש לפני תחילת הסמינר


Effect of Trailing Edge Elasticity on the Acoustic Signature of an Airfoil in Unsteady Flow