*************************************************************************** *************************************************************************** ** COPYRIGHT (C) 1996-2013, XYZ Scientific Applications, Inc. ** ** ** ** These coded instructions, statements, and computer programs contain ** ** unpublished proprietary information of XYZ Scientific Applications, ** ** Inc., and are protected by Federal copyright law. They may not be ** ** disclosed to third parties without the prior written consent of ** ** XYZ Scientific Applications, Inc. ** *************************************************************************** *************************************************************************** ABOUT THIS TEMPLATE INPUT FILE: input TEMPLATE FILE TO EDIT: template The geometry for the nacelle under consideration is assumed to be oriented in a standard way, and all surfaces for the spinner grouped into 1 TrueGrid composite surface. Similarly, all surfaces for the nacelle should be grouped into 1 TrueGrid composite surface. After the geometry is oriented and grouped, a few parameters must be set to reflect gross bounds and element sizes for the mesh. Everything else is automatic. It will take some time for the problem to run because of elliptic smoothing commands. (It takes about an hour on an HP 9000/712.) 1. ORIENT THE GEOMETRY (*) Import the IGES file for this problem using iges IGES-file-name 1 1; where IGES-file-name is the name of your IGES file. (*) Use the Environment Window labels options to label points on surfaces. Zoom way in on the tip of the spinner, and select the point at the tip. Save the coordinates by typing a 'C' in the text window, followed by a space. Then press F9 to print the coordinates of the labeled point, and hit RETURN. C 1.4171407e+02 8.4668256e-02 -2.6270186e-10 Change the parameters 'xcenter', 'ycenter', 'zcenter' to the coordinates of this point (lines 30-32 of the template file). line 29: para xcenter 1.4171407e+02 ycenter 8.4668256e-02 zcenter -2.6270186e-10 ; (*) Determine a rotational transformation to position the geometry so that (i) The positive z-axis coincides with the axis of the spinner, and points in the same direction as the spinner; (ii) All cylindrical angles of the geometry are between 0 and 180 degrees. Replace the transformation on line 36 of the input file with your transformation. line 36: ry 90 Be sure to change the name of the IGES file. line 34: iges /users/d/BOEING1/nnacell.igs 1 1 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 2. GROUP THE GEOMETRY Label the surfaces using an appropriate labels option in the Environment window. Replace the numerical range 1:14 on line 41 with the surface numbers of all surfaces of the nacelle (outer ring) line 41: sd 101 sds 1:14; Replace the numerical range 15:17 on line 45 with the surface numbers of all surfaces of the spinner. line 45: sd 102 sds 15:17 3. ESTABLISH GLOBAL BOUNDS Specify a maximum z-coordinate for the problem. This z-coordinate should be at least 20 units larger than the largest z-coordinate of any point of the geometry (30 or 40 is better) line 49: zmax 100 Specify a minimum z-coordinate for the problem. A z-plane at the chosen value must NOT be below any part of the lower edges of the nacelle or spinner surfaces. line 50: zmin -80 Specify a maximum radius. This radius must be at least 20 units larger than the largest radius of any point on the geometry (30 or 40 is better) line 51: rmax 120 4. SPECIFY ELEMENT SIZES, DENSITIES Boundary layers are automatically constructed as "offsets" of the original geometry. These layers are chosen to be about 10-12 units thick. These boundary layers are fixed, except that the number of elements in them, as well as the size of the first layer, can be specified. NUMBER OF ELEMENTS IN BOUNDARY LAYER AROUND THE NACELLE line 53: naclayer 30 THICKNESS OF THE FIRST LAYER AROUND THE NACELLE line 54: naclsiz .0001 NUMBER OF ELEMENTS IN BOUNDARY LAYER AROUND THE SPINNER line 55: spinlayer 18 THICKNESS OF THE FIRST LAYER AROUND THE SPINNER line 56: spinlsiz .001 The element size in unzoned regions determines all other densities: APPROXIMATE SIZE OF ELEMENTS IN UNZONED REGIONS line 58: elemsize 3.5 Element densities everywhere are adjusted so that elements in unzoned regions will be *about* elemsize by elemsize units. 5. RUN THE MODIFIED TEMPLATE tg i=input len=40 After the geometry is imported and additional curves are constructed the program will begin an interactive session. Make sure everything looks okay at this point. The block structure for the cylindrical mesh is as shown r = 0 _______________________________ z = zmax | | | | | | | | | | | | | | | |___|________|___________|______| | | |\ /| | | | | \ _____ / | | | | | | | | | | | | | | | | |___|________|__| | | | \ \ | | | | | | | | | | | | Z | | | | | | | / \ | | | | | | | | | | | | | | | | | | | | | | | | \ | | | | | | | ----- R |___|_______|__|_____|__|______| z = zmin / | | | | r = rmax | | > | | < | | 'naclayer' number of elements | | 'naclsiz' is the size of the first layer | | > | | < 'spinlayer' number of elements 'spinlsiz' is the size of the first layer User Specified Parameters zmax : maximum z-coordinate of mesh zmin : minimum z-coordinate of mesh rmax : maximum r-coordinate of mesh naclayer : number of elements near the nacelle naclsiz : size of the first layer near the nacelle spinlayer : number of elements near the spinner spinlsiz : size of the first layer near the spinner elemsize : rough size of elements in unzoned regions Home Page Questions, comments, suggestions Copyright © 1996-2013 XYZ Scientific Applications, Inc. 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