TimeSequenceStepperBase

TimeSequenceStepperBase is a base class for time steppers that use a sequence time values $var element = document.getElementById("moose-equation-ef5ed62a-5ac1-4e32-a067-695d7cddd8ea");katex.render("t_i", element, {displayMode:false,throwOnError:false});$ to produce time step sizes.

Failed solves

If the solver fails to obtain a converged solution for a given step, the executioner cuts back the step size and attempts to advance the time from the previous step using a smaller time step. The time step is cut back by multiplying the time step by the cutback factor, defaulting to 0.5. If this is successful, the time stepper will then attempt to use the next time in the sequence, adjusting the time step to "get back on track".

Choosing the time step size past the final time value

Suppose that $var element = document.getElementById("moose-equation-ec8ba8e2-3f00-46f8-a0e4-e5afbeb11070");katex.render("t_N", element, {displayMode:false,throwOnError:false});$ is the maximum time value provided in the sequence. This value may be less than the simulation end time $var element = document.getElementById("moose-equation-8bdc42b8-1a57-4932-9c1e-d3ec201a2d1c");katex.render("t_\\text{end}", element, {displayMode:false,throwOnError:false});$ given by the "end_time" parameter. If this is true and the current simulation time $var element = document.getElementById("moose-equation-e2778033-5c09-46cc-b825-aad10b16c6f7");katex.render("t", element, {displayMode:false,throwOnError:false});$ is past $var element = document.getElementById("moose-equation-33627237-6e1e-4ad3-9626-4388af885002");katex.render("t_N", element, {displayMode:false,throwOnError:false});$ , then by default, there will be a single, final time step that jumps to the end time:

var element = document.getElementById("moose-equation-ca46758b-23f3-4cd8-b96e-32f1d08a0e47");katex.render("\\Delta t = t_\\text{end} - t_N \\,.", element, {displayMode:true,throwOnError:false});

However, in many cases this is undesirable, such as when a steady state condition is used to terminate a transient, in which case an arbitrarily large end time is specified, leading to a very large time step size. This behavior can be altered with "use_last_dt_after_last_t". If set to true, this uses the final time step size in the sequence instead for all time past $var element = document.getElementById("moose-equation-482c7ec8-805b-42a2-8220-1db644caa669");katex.render("t_N", element, {displayMode:false,throwOnError:false});$ :

var element = document.getElementById("moose-equation-cd1d3f3f-c10b-42ce-8443-12e0a35c28f2");katex.render("\\Delta t = t_N - t_{N-1} \\,.", element, {displayMode:true,throwOnError:false});

Failed solves
Choosing the time step size past the final time value