{"id":17178,"date":"2018-10-30T09:16:57","date_gmt":"2018-10-30T09:16:57","guid":{"rendered":"https:\/\/www.simscale.com\/?page_id=17178"},"modified":"2025-07-14T11:01:25","modified_gmt":"2025-07-14T11:01:25","slug":"simulation-control","status":"publish","type":"page","link":"https:\/\/www.simscale.com\/docs\/simulation-setup\/simulation-control\/","title":{"rendered":"Simulation Control"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Under the tree item&nbsp;<em>Simulation control,<\/em>&nbsp;you can adjust different global properties and parameters regarding the simulation process. All <a href=\"https:\/\/www.simscale.com\/docs\/analysis-types\/\">analysis types<\/a> on the SimScale platform do have some of these properties in common however some of them appear only in certain analysis types. <\/p>\n\n\n\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><a href=\"https:\/\/frontend-assets.simscale.com\/media\/2025\/06\/image-19.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"826\" src=\"https:\/\/frontend-assets.simscale.com\/media\/2025\/06\/image-19-1024x826.png\" alt=\"lists of analysis types available in simscale\" class=\"wp-image-103767\" srcset=\"https:\/\/frontend-assets.simscale.com\/media\/2025\/06\/image-19-1024x826.png 1024w, https:\/\/frontend-assets.simscale.com\/media\/2025\/06\/image-19-300x242.png 300w, https:\/\/frontend-assets.simscale.com\/media\/2025\/06\/image-19-768x620.png 768w, https:\/\/frontend-assets.simscale.com\/media\/2025\/06\/image-19.png 1093w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><figcaption class=\"wp-element-caption\">Figure 1: Simulation analysis types in SimScale. Each type may have a different set of parameters for simulation control. <\/figcaption><\/figure>\n<\/div>\n\n\n<h2 id='simulation-control-general-settings' id='simulation-control-general-settings' id='simulation-control-general-settings' class=\"wp-block-heading\" id=\"simulation-control-general-settings\">Simulation Control General Settings<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">For CFD and FEA simulations, there are two general settings that can be changed under <em>Simulation control<\/em>, which are:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><em>Preferred number of CPUs<\/em>: The number of processors assigned to your simulation. Based on availability, sometimes SimScale may assign a machine with a different number of processors.<\/li>\n\n\n\n<li><em>Maximum runtime<\/em>: The maximum runtime of your simulation in real time. The simulation run stops when it goes beyond this value.<\/li>\n<\/ul>\n\n\n\n<h2 id='specific-simulation-control-settings' id='specific-simulation-control-settings' id='specific-simulation-control-settings' class=\"wp-block-heading\" id=\"specific-simulation-control-settings\">Specific Simulation Control Settings<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Find below the specific simulation control settings according to each solver incorporated into SimScale:<\/p>\n\n\n\n<h3 id='computational-fluid-dynamics' id='computational-fluid-dynamics' id='computational-fluid-dynamics' class=\"wp-block-heading\" id=\"open-foam\">Computational Fluid Dynamics<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">For the CFD <a href=\"https:\/\/www.simscale.com\/docs\/analysis-types\/#fluid-dynamics-openfoam\">analysis types<\/a> one should find the following control settings:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><em>End time<\/em>: The end time of the simulation.<\/li>\n\n\n\n<li><em>Delta t<\/em>: Time step size.<\/li>\n\n\n\n<li><em>Adjustable time step<\/em>: Enables or disables automatic time step adjustments based on specified maximum Courant number.<\/li>\n\n\n\n<li><em>Maximal Courant Number<\/em>: Maximum value of Courant number allowed. When explicit time integration schemes are used, it should be lower than 1. 0.5-0.7 is a recommended value for most cases.<\/li>\n\n\n\n<li><em>Maximal step<\/em>: Maximum time step size during runtime.<\/li>\n\n\n\n<li><em>Max alpha co<\/em>: Defines a Courant number based on the interface velocity.<\/li>\n\n\n\n<li><em>Write control<\/em>: Algorithm of data generation.<\/li>\n\n\n\n<li><em>Write interval<\/em>: Frequency of generating data. This is based on the <em>Write control<\/em> for post-processing.<\/li>\n\n\n\n<li><em>Potential foam initialization<\/em>: Activates or deactivates the solution of a potential flow field.<\/li>\n\n\n\n<li><em>Decompose algorithm<\/em>: Algorithm controlling the decomposition of mesh into a number of parts for a parallel run.<\/li>\n<\/ul>\n\n\n\n<div class=\"hw-block hw-note hw-note--warning hw-note\">\n    <div class=\"hw-note__title\">\n        <p class=\"hw-note__titleText\"><i class=\"fa fa-exclamation-circle\" aria-hidden=\"true\"><\/i>Important<\/p>\n    <\/div>\n    <div class=\"hw-note__body\">\n        <p>For a &#8220;Steady-state&#8221; analysis, <b>End time value<\/b> is a &#8216;pseudo&#8217; time value and holds no physical meaning. It determines the number of overall iterations done to reach a steady-state, calculated as \u201c(end time) \/ (time step length)\u201d.<\/p>\n    <\/div>\n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\">To comprehend each term defined above in detail please visit our <strong>&#8216;Simulation control for fluid analysis&#8217;<\/strong> documentation. <\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-wp-embed is-provider-simscale wp-block-embed-simscale\"><div class=\"wp-block-embed__wrapper\">\n<blockquote class=\"wp-embedded-content\" data-secret=\"ETw8JVKS3c\"><a href=\"https:\/\/www.simscale.com\/docs\/simulation-setup\/simulation-control-fluid\/\">Simulation Control for Fluid Analysis<\/a><\/blockquote><iframe loading=\"lazy\" class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; visibility: hidden;\" title=\"&#8220;Simulation Control for Fluid Analysis&#8221; &#8212; SimScale\" src=\"https:\/\/www.simscale.com\/docs\/simulation-setup\/simulation-control-fluid\/embed\/#?secret=NgUH2uDoqQ#?secret=ETw8JVKS3c\" data-secret=\"ETw8JVKS3c\" width=\"500\" height=\"282\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><\/figure>\n\n\n\n<h3 id='finite-element-analysis' id='finite-element-analysis' id='finite-element-analysis' class=\"wp-block-heading\" id=\"codeaster\"><strong>Finite Element A<\/strong>nalysis<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">For the FEA <a href=\"https:\/\/www.simscale.com\/docs\/analysis-types\/#solid-mechanics-code-aster\">analysis types<\/a> one should find the following control settings:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Linear analysis<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><em>Pseudo time stepping<\/em>: Increments to subdivide the solution into smaller steps that makes it easier to converge.<\/li>\n\n\n\n<li><em>Static time steps<\/em>: Defines static time step for simulation.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Non-linear and Dynamic analysis<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><em>Time step definiti<\/em>on: Controls how the time step will be defined.<\/li>\n\n\n\n<li><em>Simulation interval<\/em>: The value for <em>t<\/em> if the simulation terminates.<\/li>\n\n\n\n<li><em>Maximum time step length<\/em>: Maximum interval for the calculated time step.<\/li>\n\n\n\n<li><em>Minimum time step length<\/em>: Minimum time step allowed.<\/li>\n\n\n\n<li><em>Maximum residual<\/em>: The maximum residual allowed before the simulation fails.<\/li>\n\n\n\n<li><em>Retiming event<\/em>: Controls the time step adaptation.<\/li>\n\n\n\n<li><em>Time step calculation<\/em>: Method for time step computation.<\/li>\n\n\n\n<li><em>Additional Newton iterations<\/em>: Percentage of additional Newton iterations allowed when the simulation has not converged after the maximum number of Newton iterations has been reached.<\/li>\n\n\n\n<li><em>Number of subdivisions<\/em>: Number of equal subdivisions of a time step in case of adaptation.<\/li>\n\n\n\n<li><em>Max subdivision depth<\/em>: Maximum depth for time step subdivisions. The simulation stops when it goes over this value. If after a number of n consecutive subdivisions the solution does not converge, it will stop and not do the (n+1)th subdivision.<\/li>\n\n\n\n<li><em>Newton iteration threshold<\/em>: Threshold for the number of maximum Newton iterations before the time step increases. If the number of Newton iterations required to converge a time step is smaller than this number and the current time increment is smaller than initially defined, the time increment will be increased for the next time step.<\/li>\n\n\n\n<li><em>Time step augmentation<\/em>: Percentage for time step increment after Newton iteration threshold is reached.<\/li>\n\n\n\n<li><em>Write control definition<\/em>: Frequency of intermediate results saved.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">To comprehend each term defined above in detail please visit our <strong>&#8216;Simulation control for structural analysis&#8217;<\/strong> documentation.<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-wp-embed is-provider-simscale wp-block-embed-simscale\"><div class=\"wp-block-embed__wrapper\">\n<blockquote class=\"wp-embedded-content\" data-secret=\"5gc3YnioDc\"><a href=\"https:\/\/www.simscale.com\/docs\/simulation-setup\/simulation-control-structural-analysis\/\">Simulation Control for Structural Analysis<\/a><\/blockquote><iframe loading=\"lazy\" class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; visibility: hidden;\" title=\"&#8220;Simulation Control for Structural Analysis&#8221; &#8212; SimScale\" src=\"https:\/\/www.simscale.com\/docs\/simulation-setup\/simulation-control-structural-analysis\/embed\/#?secret=bbpnf8wuQV#?secret=5gc3YnioDc\" data-secret=\"5gc3YnioDc\" width=\"500\" height=\"282\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><\/figure>\n\n\n\n<h3 id='lattice-boltzmann-method-lbm' id='lattice-boltzmann-method-lbm' id='lattice-boltzmann-method-lbm' class=\"wp-block-heading\" id=\"lattice-boltzmann-method-lbm\">Lattice Boltzmann Method (LBM)<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">For the LBM <a href=\"https:\/\/www.simscale.com\/docs\/analysis-types\/#fluid-dynamics-lbm-solver\">analysis types<\/a> supported by Pacefish\u00ae\\(^1\\) one should find the following control settings: <\/p>\n\n\n\n<p class=\"wp-block-paragraph\" id=\"incompressible-lbm\"><strong>Incompressible (LBM)<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><em>End time<\/em>: The end time of the simulation in simulation time.<\/li>\n\n\n\n<li><em>Maximum runtime<\/em>: The maximum runtime of your simulation in real time. When it goes over this, the simulation run will stop.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\" id=\"pedestrian-wind-comfort-pwc\"><strong>Pedestrian Wind Comfort (PWC)<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><em>Maximum runtime per direction<\/em>: The maximum runtime of your simulation in real time for each wind direction. The simulation run will stop when it goes over this value. <\/li>\n\n\n\n<li><em>Number of fluid passes<\/em>: The number of passes the air makes through the domain.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">You can find more details on how to control these parameters here.<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-wp-embed is-provider-simscale wp-block-embed-simscale\"><div class=\"wp-block-embed__wrapper\">\n<blockquote class=\"wp-embedded-content\" data-secret=\"azzSMTEPdN\"><a href=\"https:\/\/www.simscale.com\/docs\/analysis-types\/pedestrian-wind-comfort-analysis\/simulation-control\/\">Simulation Control for Wind Comfort<\/a><\/blockquote><iframe loading=\"lazy\" class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; visibility: hidden;\" title=\"&#8220;Simulation Control for Wind Comfort&#8221; &#8212; SimScale\" src=\"https:\/\/www.simscale.com\/docs\/analysis-types\/pedestrian-wind-comfort-analysis\/simulation-control\/embed\/#?secret=UiKc28mxct#?secret=azzSMTEPdN\" data-secret=\"azzSMTEPdN\" width=\"500\" height=\"282\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><\/figure>\n\n\n\n<h2 id='multi-purpose-analysis' id='multi-purpose-analysis' id='multi-purpose-analysis' class=\"wp-block-heading\" id=\"multi-purpose-analysis\">Multi-purpose Analysis <\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">For the Multi-purpose analysis, the simulation control parameters are mostly similar to the ones discussed for CFD ones discussed above and are detailed in the <a href=\"https:\/\/www.simscale.com\/docs\/analysis-types\/subsonic-cartesian\/#simulation-control\">Multi-purpose analysis documentation<\/a>.<\/p>\n\n\n\n<h2 id='electromagnetics-analysis' id='electromagnetics-analysis' class=\"wp-block-heading\" id=\"electromagnetics-analysis\">Electromagnetics Analysis<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">For the Electromagnetic analysis type the simulation control parameters, <em>Number of processors<\/em> and <em>Maximum runtime<\/em> are already discussed above.<\/p>\n\n\n\n\n<div class='hw-block hw-references hw-references'>\n    <p class='hw-references__title'>References<\/p>\n    <ul class='hw-references__list'>\n\n        <li><cite><a href=\"https:\/\/www.numeric.systems\/pacefish\" target=\"_blank\" rel=\"nofollow noopener\">https:\/\/www.numeric.systems\/pacefish<\/a><\/cite><\/li>\n    <\/ul>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Under the tree item&nbsp;Simulation control,&nbsp;you can adjust different global properties and parameters regarding...","protected":false},"author":86,"featured_media":0,"parent":17179,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"templates\/template-documentation.php","meta":{"_acf_changed":false,"_crdt_document":"","inline_featured_image":false,"footnotes":""},"class_list":["post-17178","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.simscale.com\/wp-json\/wp\/v2\/pages\/17178","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.simscale.com\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.simscale.com\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.simscale.com\/wp-json\/wp\/v2\/users\/86"}],"replies":[{"embeddable":true,"href":"https:\/\/www.simscale.com\/wp-json\/wp\/v2\/comments?post=17178"}],"version-history":[{"count":0,"href":"https:\/\/www.simscale.com\/wp-json\/wp\/v2\/pages\/17178\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/www.simscale.com\/wp-json\/wp\/v2\/pages\/17179"}],"wp:attachment":[{"href":"https:\/\/www.simscale.com\/wp-json\/wp\/v2\/media?parent=17178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}