elt number is used for estimating the convective coefficient when
% calculating the thermal convection between particles and the
% surrounding fluid.
%
% This super-class defines abstract methods that must be implemented in
% the derived *sub-classes*:
%
% * <Nusselt_Sphere_RanzMarshall.html Nusselt_Sphere_RanzMarshall>
% * <Nusselt_Sphere_Whitaker.html Nusselt_Sphere_Whitaker>
%
classdef Nusselt < handle
    %% Constant values
    properties (Constant = true, Access = public)
        % Types of model
     