TUFLOW Message 3043 - Revision history

Melissa.Moghanloo at 00:18, 3 March 2023

2023-03-03T00:18:24Z

← Older revision		Revision as of 10:18, 3 March 2023
Line 18:		Line 18:


	\|prelink=[[TUFLOW_Message_3042\|Message 3042]]
	\|uplink=[[3xxx_TUFLOW_Messages\|3xxx Messages]]		\|uplink=[[3xxx_TUFLOW_Messages\|3xxx Messages]]
	\|nextlink=[[TUFLOW_Message_3044\|Message 3044]]
	}}		}}

Emilie Nielsen at 06:49, 2 March 2023

2023-03-02T06:49:11Z

@@ Line 1: / Line 1: @@
 {{TUFLOW_Message
-|tuflow_message=ERROR 3043: Model unstable.
+|tuflow_message=ERROR 3043 - Model unstable.
 <br>
-|alt_msg=ERROR 3043: Too many consecutive failed step attempts.
+|alt_msg=ERROR 3043 - Too many consecutive failed step attempts.
 |type=[[ERROR]]

Melissa.Moghanloo at 05:22, 13 July 2022

2022-07-13T05:22:22Z

← Older revision		Revision as of 15:22, 13 July 2022
Line 20:		Line 20:


	\|discussion_page=* [[Talk:TUFLOW Message 3043\|Discuss Message 3043]]
	\|link3=''
	\|link4=''
	\|prelink=[[TUFLOW_Message_3042\|Message 3042]]		\|prelink=[[TUFLOW_Message_3042\|Message 3042]]
	\|uplink=[[3xxx_TUFLOW_Messages\|3xxx Messages]]		\|uplink=[[3xxx_TUFLOW_Messages\|3xxx Messages]]

Teegan.Burke: Created page with "{{TUFLOW_Message |tuflow_message=ERROR 3043: Model unstable.
|alt_msg=ERROR 3043: Too many consecutive failed step attempts. |type=ERROR |message_desc=When using a..."

2018-04-20T00:53:50Z

Created page with "{{TUFLOW_Message |tuflow_message=ERROR 3043: Model unstable. <br> |alt_msg=ERROR 3043: Too many consecutive failed step attempts. |type=ERROR |message_desc=When using a..."

New page

{{TUFLOW_Message
|tuflow_message=ERROR 3043: Model unstable.
<br>
|alt_msg=ERROR 3043: Too many consecutive failed step attempts.

|type=[[ERROR]]
|message_desc=When using adaptive timestepping, should a timestep need to be repeated more than 10 times consecutively, the solution stops.
|suggestions=If using the adaptive timestepping (the default), the HPC timestep is calculated using the hydraulic conditions from the end of the previous timestep. If the hydraulic conditions have changed significantly it is possible for one or more of the Nu, Nc, Nd control number criteria to be violated at one or more locations within the model. For example, a sudden change in rainfall from one timestep to the next (which occurs with stepped rainfall boundaries) would potentially cause a violation. The HPC solver, by default, treats a 20% exceedance of a control number as a violation and will implement a repeat timestep feature.<br>

HPC uses a repeat timestep feature to maintain unconditional stability. The repeat timestep feature involves retaining the complete hydraulic solution from the previous (good) timestep. Should a control number anywhere within the model be exceeded by more than 20%, the solution reverts to the retained timestep, the timestep is reduced and then repeated. Should a timestep need to be repeated more than ten times consecutively, the solution stops. The simulation will also stop if the default minimum permissible timestep of 0.1 seconds has been reached. This value can be manually adjusted using 'Timestep Minimum' TCF command. These occurrences are rare and potentially an indication of poor model schematisation or poor data.

Each timestep is also tested for the occurrence of NaNs. A NaN is “Not a Number” and occurs due to undefined mathematical calculations such as a divide by zero or square root of a negative number. The occurrence of a NaN is also indicative of a sudden instability. Should a NaN occur, the repeat timestep feature is implemented.

To review and isolate the location of the minimum timestep, look at:
*Console window and .hpc.tlf file
*.hpc.dt.csv file (this file contains every timestep)
*_HPC.csv file output in the results folder (has the number of repeated timesteps for a time interval in the nRS_NaNs and nRS_HCNs column)
*_messages layer (location of repeated timesteps)
*“Minimum dt” map output (excellent for identifying the location of the minimum timestep adopted – add “dt” to “Map Output Data Types ==”)

|discussion_page=* [[Talk:TUFLOW Message 3043|Discuss Message 3043]]
|link3=''
|link4=''
|prelink=[[TUFLOW_Message_3042|Message 3042]]
|uplink=[[3xxx_TUFLOW_Messages|3xxx Messages]]
|nextlink=[[TUFLOW_Message_3044|Message 3044]]
}}

TUFLOW Message 3043 - Revision history

Melissa.Moghanloo at 00:18, 3 March 2023

Emilie Nielsen at 06:49, 2 March 2023

Melissa.Moghanloo at 05:22, 13 July 2022

Teegan.Burke: Created page with "{{TUFLOW_Message |tuflow_message=ERROR 3043: Model unstable. |alt_msg=ERROR 3043: Too many consecutive failed step attempts. |type=ERROR |message_desc=When using a..."

Teegan.Burke: Created page with "{{TUFLOW_Message |tuflow_message=ERROR 3043: Model unstable.
|alt_msg=ERROR 3043: Too many consecutive failed step attempts. |type=ERROR |message_desc=When using a..."