#TITLE_ALTERNATIVE#

• Main Author: ABDUL KOHAR (NIM : 13604039); Pembimbing : Dr. Ir. Moch. Agoes Moelyadi, RUSLAN
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/17116
• Institution: Institut Teknologi Bandung

Availability of energy resources that has been declining forces human being to consume energy efficiently. In aeronautics, there is a term called lift-to-drag ratio or aerodynamic efficiency that affects the performance of an aircraft. There are three methods to figure out the lift-to-drag ratio, i.e. experiment, analytic, and numeric. Numeric or CFD is cheaper than the experiment and is more capable to solve the problem than the analytic. One of important things of the simulation system of CFD is discretization space or grid generation. There are two classes of grid generation, structured and unstructured grid. <br /> <br /> <br /> <br /> <br /> In this work, a program is constructed to generate grid around airfoil in FORTRAN language. The unstructured grid is used since it can easily generate grid in complex geometry. Delaunay triangulation is faster than other unstructured grid techniques, i.e. Advancing Front and Quad-tree technique. First, boundary points are triangulated. To position variables that will be obtained, some interior points are then required to replace the physical domain by evaluating aspect ratio (AR) and area (A) of triangles. If aspect ratio and area fulfill the circumstances, AR > ARlim and A > Alim, the center of triangles are then inserted into existing Delaunay triangulation as interior points. Smoothing is then performed, when the insertion of interior points in each step has finished, using Laplacian smoothing. In order to obtain gradual size of triangles along flow domain, the physical domain is then divided into four regions which each region has area limit, Alim. To control space between body and points those are adjacent to it, before inserting the interior points, the points obtained from normal vector of edges connecting airfoil points are inserted. Obtained grid is then visualized using MATLAB. An inviscid solver is utilized to figure out aerodynamic characteristics at condition M&#8734;=0.729 and &#945;=2.31o and to evaluate the obtained grid. In this work, the unstructured grid program can successfully generate grid around single and multi element, despite unstructured grid around airfoil is not better than structured grid on flow solution. Smoothing process can increase grid quality such that coefficient of pressure distribution obtained is more suitable with experimental data. The best cl/cd of airfoil RAE-2822 is 16.35. <br />