A set of particle locating algorithms not requiring face belonging to cell connectivity data

Existing efficient directed particle locating (host determination) algorithms rely on the face belonging to cell relationship (F2C) to find the next cell on the search path and the cell in which the target is located. Recently, finite volume methods have been devised which do not need F2C. Therefore, existing search algorithms are not directly applicable (unless F2C is included). F2C is a major memory burden in grid description. If the memory benefit from these finite volume methods are desirable new search algorithms should be devised. In this work two new algorithms (line of sight and closest cell) are proposed which do not need F2C. They are based on the structure of the sparse coefficient matrix involved (stored for example in the compressed row storage, CRS, format) to determine the next cell. Since F2C is not available, testing a cell for the presence of the target is not possible. Therefore, the proposed methods may wrongly mark a nearby cell as the host in some rare cases. The issue of importance of finding the correct host cell (not wrongly hitting its neighbor) is addressed. Quantitative measures are introduced to assess the efficiency of the methods and comparison is made for typical grid types used in computational fluid dynamics. In comparison, the closest cell method, having a lower computational cost than the family of line of sight and the existing efficient maximum dot product methods, gives a very good performance with tolerable and harmless wrong hits. If more accuracy is needed, the method of approximate line of sight then closest cell (LS-A-CC) is recommended.