Field Forces - simphysoftwares/SimPHY-docs GitHub Wiki

Once the World is created there are a number of things you may want to configure. The most common configurable item is gravity. The default gravity is 9.8 m/s2 pointing in the negative y direction.

To change gravity right click simulation node in simulation tree view to open popup menu shown, or you can click Edit World in Windows tab

Field where to find

Field input

Edit/Add new Field and click apply for changes to take effect.

SimPhy supports setting up of various fields other than gravity. To set up fields, edit world settings. The fields and their effect are as follows

Fields

You can add fields as shown in the GIF or by right clicking in the working area and then selecting world settings then choosing Field and then choose Add EM/Buoyancy Field. Adding fields

Gravity: The default gravity is 9.8 m/s2 pointing in the negative y direction. You can set the Gravity Scale or Gravity factor (with default value 1) of individual objects to experience different gravity and behave differently in the Property Panel.

The gravitational force on an object is calculated as Force = mass x gravity x Gravity Scale

Electrostatic field: Electrostatic field (in N/C) added to the world, applies force on an object if and only if it has non zero charge and it is inside the bounds of the field.

The electrostatic force on an object is calculated as Force = charge x electrostatic field

Magnetic field: Magnetic field (in Wb/m2 perpendicular to the plane) added to the world, apply force on an object if and only if it has non zero charge and it is moving.

The magnetic lorentz force on an object is calculated as Force = charge x speed x magnetic field

and is perpendicular to the velocity

Buoyancy and drag: Buoyancy can be added to a region representing hypothetical liquid in that region. The density and viscosity of liquid can be changed while adding/editing field.

The buoyancy force on an object is calculated as

Force = [area submerged] X [density of liquid] X [gravity] -[viscosity]*[speed]

Additional correction for lift is also taken into account based on the geometry of the object.

Air Drag: Air drag can be simulated using Buoyancy field with small values of density (e.g. 0.001) and small value of viscosity (e.g 0.001).

Note:

  • Electric and magnetic forces will be experienced by bodies having non zero charge.
  • For how to add change to body, have a look at property panel
  • Fields like buoyancy have some default hard coded settings for drag coefficient etc.
  • All Fields are measured in the SI System of units.