Discrete Conservation Law on Curved Surfaces
  In this paper we shall introduce a simple, effective numerical method for finding differential operators for scalar and vector-valued functions on surfaces. The key idea of our algorithm is to develop an intrinsic and unified way to compute directly the partial derivatives of functions defined on triangular meshes which are the discretization of regular surfaces under consideration. Most importantly, the divergence theorem and conservation laws on triangular meshes are fulfilled. 
Sheng-Gwo Chen, Jyh-Yang Wu
cs.CG math.NA physics.comp-ph