We consider solutions of adjoint and self-adjoint continuum mechanics problems for evaluation of physical, mechanical, and thermophysical properties of various structures and media. A software implementation of mathematical models for selfadjoint problems is developed using scientific application software package «Composite-NK» which provides coupling and modeling of diverse physical processes. Visual design techniques are used for assembling the necessary application programs from prearranged code blocks, since numerical simulations of different processes are based on similar algorithms. Flowcharts are automatically translated into a sequence of operations. Open source software development is supported by reference help system with automatic analysis of modules source codes and access provisioning to modules structures. This technique is time reducing and especially helpful for solving non-standard problems with computers. In the paper, examples are provided for solving several problems: (a) heat and mass transfer in a viscous medium; (b) microstructure stress calculation for spatially reinforced membrane; (c) steam water mixture filtration in a porous medium (for the problem of concrete fire resistance).