document: Contact methods have been developed and used in Lagrangian staggered-grid hydrodynamic (SGH) calculations for many years. Early examples of contact methods are discussed in Wilkins [37] and Cherry et al. [7]. Hallquist et al. [17] provides an overview of multiple contact algorithms used in various Lagrangian SGH codes dating back to HEMP [37]. Of particular interest, Hallquist et al. [17] describes the contact surface scheme used in TOODY [31] and later implemented in DYNA2D [36]. The contact method of TOODY uses a master–slave approach. The goal of this approach is to treat the nodes on the contact surface in a manner similar to an internal node. The physical properties of the slave surface are interpolated to a ghost mesh (termed phony elements in [17]) that overlays the slave zones. The physical properties are interpolated from the slave surface to the ghost zones using surface area weights. The surface area weights are equal to the ratio of the ghost zone surface area to the surface area of the master surface. The contact surface method for nodal-based Lagrangian cell-centered hydrodynamics (CCH) presented in this paper will use surface area weights similar in concept to those in TOODY. Following the area fraction approach of TOODY may seem retrospective; however, using surface area weights naturally extends to the new CCH methods that solve a Riemann-like problem at the node of a zone [10,24,25,3].
extractive_keyphrases: area fraction approach cch contact algorithms contact method contact methods contact surface dyna2d ghost mesh ghost zones ghost zone surface area hemp internal node lagrangian sgh master–slave approach master surface nodes phony elements sgh slave surface slave zones surface area toody
abstractive_keyphrases: cch methods cell-centered hydrodynamics contact surface method contact surface scheme nodal-based lagrangian cell-centered hydrodynamics solve a riemann-like problem at the node of a zone staggered-grid hydrodynamic