The spherical capacitor example has been designed to demonstrate the parameter sweep feature in combination with the capacitance calculation. It is also good to validate the simulation accuracy, since an analytical solution is available.
The structure consists of a small sphere of perfectly conducting material (PEC), embedded in a larger vacuum sphere. The background material is set to PEC. Three tangential symmetry conditions are used to reduce the calculation domain and therefore the calculation time. Furthermore a parameter "dr" was defined representing the distance of the inner sphere to the outer sphere.
The capacitance of a spherical capacitor is given by:
Where Ro is the outer radius which is equal to Ri+dr.
The default solver settings provided by the electrostatic template are changed: The hexahedral mesh type is activated and the adaptive mesh refinement is switched off. To perform electrostatic calculations a potential value of 1V is defined at the inner sphere. The perfectly conducting background material is set to 0V by default.
The parameter "dr" is considered for variation between 0.5 and 5 using the parameter sweep feature. Running the parameter sweep the capacitance matrix of the spherical capacitor is monitored.
By selecting the capacitance table in the navigation tree one can study the influence of the parameter "dr" on the capacitance of the structure. Moreover one can compare the numerically computed capacitance value to the analytic value.