Question

I have an issue with a SACS file, which runs in SACS 16.0, but in SACS 16.1 I am getting an error message “NO STREAM FUNCTION SOLUTION IS POSSIBLE”.

Answer

The error message “NO STREAM FUNCTION SOLUTION IS POSSIBLE” occurs when the stream wave calculation does not converge.

Starting from SACS 16.1 and later, the program includes a breaking wave height check in accordance with DNV-RP-C205 (2014), Equation 3.4.6.1. This revision results in a smaller allowable breaking wave height range compared to earlier versions.

• In older versions, a given wave height might not exceed the breaking limit, and therefore, no error was triggered.
• In updated versions, the same wave may now be classified as breaking.

When the specified wave height exceeds the breaking wave limit, Seastate and Wave Response will skip stream wave creation because steep waves often cause the stream wave calculation to diverge. This condition leads to the error message.

Resolution

To avoid this error, reduce the input wave height so that it remains below the breaking wave limit defined by the updated DNV-RP-C205 criteria.