سال انتشار: ۱۳۸۶
محل انتشار: هفتمین همایش انجمن هوافضای ایران
تعداد صفحات: ۱۰
Carmine GOLIA – Faculty of Engineering – Second University of Naples – Italy, Department of Aerospace and Mechanical Engineering
Leading-edge devices and single or multiple slotted flaps are used on modern high performance airplanes to provide adequate low speed performances both in take-off and landing phases. The optimization procedures of such high lift systems, require the knowledge of the flow field around all the elements. This is quite complicated by the presence of cove separation bubbles, of multi boundary layers and wake interactions, of laminar/turbulent transition, separation/reattachment /confluence all phenomena with unsteady intermittent and pulsating features. The classical analysis (coupling Potential Field with Boundary Layer) is not fully capable to describe the strong interactions. CFD is quite severe and not always capable to match flight Reynolds numbers. Wind tunnel testing (long-lasting and extremely expensive) is conceived as the last tool of the design chain. Main scope of this work is to analyze if Blob Vortex Method can be useful in the visualization of the flow around multiple elements airfoils, in order to verify the preliminary optimality of settings and geometries. The paper consider Lagrangian analysis of two dimensional flow problems described by velocity vorticity formulation with a Vortex Blob Method based on Biot-Savart law combined with BEM for computing the velocity, and a Core Spreading Method for computing the vortex diffusion. It results a very simple and efficient instrument to visualize vortex blob paths around multi-element airfoil components and gaps. The code is tested by considering plain NACA 64a-010 airfoil, 2 element (slat and main), and 3 element (slat, main, slotted flap) systems. All these configurations are tested with small variations of the geometries and settings in order to verify the credibility of ensuing flow fields and resulting global forces, with the sole scope to substantiate the suitability of the Vortex Blob Method to speed up the preliminary optimization design loop of a multi-element high-lift airfoil system.