Preliminary aerodynamic investigation of box-wing configurations using low fidelity codes
Abstract: This work outlines the different aerodynamic aspects of box-wing design i.e. an unconventional aircraft design configuration exhibiting the capability of reducing induced drag. Being a nonplanar concept, the basic aerodynamic features differ from conventional designs. To understand these features and their influence on box-wing aerodynamics, parameter variations have been conducted while Munk's theorem is validated for stagger and sweep. In this process, several important aspects of box-wing are highlighted. An optimization algorithm has been implemented by considering all the design variables collectively to find the global maximum for the box-wing design. All these investigations laid down the important aerodynamic features of box-wing and also proved a method for estimating the reduction in induced drag.To conduct these investigations, vortex lattice methods (VLM) are used. Non planar systems have certain limitations for best operations which provide maximum induced drag reduction. These limitations are examined and applied in the form of constant and specified lift distributions in the analysis. Furthermore, it is concluded that vortex lattice methods do capture the reduction in induced drag correctly if the limitations of span loading are maintained during the analysis. Based on previous results obtained, Euler inviscid analysis for a selected box-wing and a reference wing are carried out. The results of Euler inviscid analysis show good agreement with the results achieved by vortex lattice method in drag reduction. Therefore, VLM methods are capable of analyzing box-wing (and multi planar systems) to a good accuracy. At the same time, transonic airfoil selection is identified as one of the key factors in designing a commercial box-wing aircraft.This study is closed up by discussing different potential advantages for the aviation industry and discusses if a box-wing commercial aircraft should be made reality. On the whole, this work looks into a possible way of investigating futuristic multi planar aircraft configurations by using low fidelity aerodynamic codes.
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