-wlosses: computation of wall losses with the pertubation formula

We enter the section -wlosses. Its menu is:

 ##############################################################################
 # Flags: nomenu, prompt, message,                                            #
 ##############################################################################
 # section: -wlosses                                                          #
 ##############################################################################
 # symbol    = e_1                                                            #
 # quantity  = e                                                              #
 # solution  = 1                                                              #
 # frequency = auto                     -- [auto | Real]                      #
 #                                                                            #
 #                                                                            #
 # @metalpower : undefined             (symbol: undefined)                    #
 ##############################################################################
 # doit, ?, return, end, help                                                 #
 ##############################################################################

Since the power losses are caused by currents flowing in metal, and the currents are proportional to the tangential H-field at the metallic walls, we have to enter a H-field as symbol or quantity.

 -wlosses
    quantity= h
    solution= 1
    doit

The wall losses are computed as:

$$\int \int \frac{H^2}{1 /(2 \kappa \delta)} dF \nonumber$$

$$\frac{1}{\delta} = \sqrt{ \pi f \mu _0 \kappa } \nonumber$$

The integral is performed over all metallic surfaces that would appear in a plot as produced by the section -3darrowplot. This implies, that wall losses are NOT computed for electric symmetry planes, since the material on the symmetry planes are not shown in -3darrowplot.

The conductivities that are used in the pertubation formula may be entered in the section -material. The result of the computation is available as the symbolic variable @metalpower.

The resulting menu (with the default conductivities of copper) is

 ##############################################################################
 # Flags: nomenu, prompt, message,                                            #
 ##############################################################################
 # section: -wlosses                                                          #
 ##############################################################################
 # symbol    = h_1                                                            #
 # quantity  = h                                                              #
 # solution  = 1                                                              #
 # frequency = auto                     -- [auto | Real]                      #
 #                                                                            #
 #                                                                            #
 # @metalpower : 16.21816e-6           (symbol: h_1)                          #
 ##############################################################################
 # doit, ?, return, end, help                                                 #
 ##############################################################################