I just receive fluent 5.5 and install it on my computer. Luckyly when i read my old case and data (version 5.3, it work before) in fluent 5.5, it doesn't work. There's many error on it (error object()???). Anyone can help???. Should i turn back to 5.3???

The differences from the Fluent published release notes:

2. New Features in FLUENT 5.5

New features in FLUENT 5.5 are listed below.

Solver

Monitoring of forces and moments on individual walls (see the User's Guide Addendum for details)

Models

Maximum number of species increased to 50

Momentum sinks for solidification with the phase change model (see the User's Guide Addendum for details)

Surface tension and wall adhesion between more than two phases in the VOF model (see the User's Guide Addendum for details)

Improved accuracy for particle tracking in the discrete phase model (see the User's Guide Addendum for details)

Real gas model on Windows NT

Parallelization of thin-plate conduction model

Boundary conditions

Two-way coupling with the GT-Power 1D gas dynamics and engine simulation code (see the User's Guide Addendum for details)

Injection definitions for the discrete phase included in the boundary condition file created with the write-bc text command

Postprocessing

Range detection based on minimum and maximum values on selected surfaces (see the User's Guide Addendum for details)

More convenient ways to list and select zones and surfaces (see the User's Guide Addendum for details)

Residuals for additional solution variables available for plotting for the segregated solver as well as the coupled solvers (see the User's Guide Addendum for details)

Plotting of user-defined vectors (see the User's Guide Addendum for details)

Availability of wall normal distance for all models (see the User's Guide Addendum for details)

File handling

Mesh import from CGNS (CFD general notation system) format on a limited number of platforms (see Section 4 and the User's Guide Addendum for details)

Data export to ANSYS (on a limited number of platforms), Abaqus (3D only), and CGNS formats (see Section 4 and the User's Guide Addendum for details)

Export of specified function data to NASTRAN (see the User's Guide Addendum for details)

Documentation

List of commands in the text interface (see the Text Command List)

3. New Features in Previous Releases of FLUENT 5

3.1 FLUENT 5.4

New features in FLUENT 5.4 are listed below.

Solver

Floating operating pressure option (see the User's Guide Addendum for details)

Monitors for minimum and maximum values of variables (see the User's Guide Addendum for details)

Models

Thin-plate conduction in walls (see the User's Guide Addendum for details)

Customization of source terms in Reynolds stress equations for Reynolds stress turbulence model (see the User's Guide Addendum for details)

Boundary conditions

Copying of boundary conditions from one zone to others of the same type (see the User's Guide Addendum for details)

Reading and writing of boundary conditions to a file (see the User's Guide Addendum for details)

Postprocessing

Reports of minimum and maximum values of variables (see the User's Guide Addendum for details)

File handling

List of recently read or written case files for quick reading (see the User's Guide Addendum for details)

Export of heat flux data (including radiation) to a generic file (see the User's Guide Addendum for details)

User-defined scalar transport equations

Maximum number of equations increased to 50

User-defined functions

Ability to store variables computed by a UDF (see the UDF User's Guide for details)

Ability to execute UDFs on demand (see the UDF User's Guide for details)

Ability to write a user-defined section to a case or data file and read it back in (see the UDF User's Guide for details)

thanks for your answer Ugur, but that's not my point. Of course a new release will add new features, but we can't guarantee that its better (it can be worse from the predecessor). In my Application, there's report problem for FLUENT 5.5, and we never met this problem using 5.3 version, i.e. if you viewing graphic window, you must close the previous window, otherwise you'll get the segment violation error. I mean, this my application problem or Fluent problem???. As you know, graphic window error is not documented. hehe....

regards, confused