How to use a transient boundary profile in Fluent 6

2017-01-19 by:CAE仿真在线来源:互联网

Problem:

A transient boundary condition can be defined in FLUENT 6 with User Defined Functions (UDFs) or boundary profiles. It is very easy to write a UDF to define a temporally varying boundary condition by following the example in the UDF User's Guide, Section 10.1.2. However, in some cases where the relationship between time and the dependent variable is very simple, it may be easier to use a time dependent boundary profile. The use of profiles to specify transient boundary conditions, as documented in the Addendum to the FLUENT 5 User's Guide, is described below.

Resolution:
Transient Boundary Conditions There are two ways you can specify transient boundary conditions: 1. transient profile with a format similar to the standard boundary profiles described in Section 6.24 of the FLUENT 5 User's Guide 2. transient profile in a tabular format !! For both methods, the boundary condition will vary only in time; it must be spatially uniform. !! 1. Standard Transient Profiles ----------------------------------------------- The format of the standard transient profile file (based on the profiles described in Section 6.24 of the FLUENT 5 User's Guide) is ((profile-name transient n periodic?) (field_name-1 a1 a2 a3 .... an) (field_name-2 b1 b2 b3 .... bn) . . . . (field_name-r r1 r2 r3 .... rn)) One of the field_names should be used for the time field, and the time field section must be in ascending order. The periodic? entry indicates whether or not the profile is time-periodic. Set it to 1 for a time-periodic profile, or 0 if the profile is not time-periodic. An example is shown below: ((sampleprofile transient 3 1) (time 1 2 3 ) (u 10 20 30 ) ) You can read this file into FLUENT using the Boundary Profiles panel or the File/Read/Profile... menu item. Define >> Profiles... File >> Read >> Profile... See Section 6.25.3 in the FLUENT 6 User's Guide for details. 2. Tabular Transient Profiles -------------------------------------------- The format of the tabular transient profile file is profile-name n_field n_data periodic? field-name-1 field-name-2 field-name-3 .... field-name-n_field v-1-1 v-2-1 ... ... ... ... v-n_field-1 v-1-2 v-2-2 ... ... ... ... v-n_field-2 . . . . . v-1-n_data v-2-n_data ... ... ... ... v-n_field-n_data One of the field-names should be used for the time field, and the time field section must be in ascending order. The periodic? entry indicates whether or not the profile is time-periodic. Set it to 1 for a time-periodic profile, or 0 if the profile is not time-periodic. An example is shown below: sampletabprofile 2 3 1 time u 1 10 2 20 3 30 This file defines the same transient profile as the standard profile example above. You can read this file into FLUENT using the read-transient-table text command. file/read-transient-table