KIVA-4: An unstructured ALE code for compressible gas flow with sprays

The KIVA family of codes was developed to simulate the thermal and fluid processes taking place inside an internal combustion engine. In this latest version of this open source code, KIVA-4, the numerics have been generalized to unstructrured meshes. This change required modifications to the Lagrangian phase of the computations, the pressure solution and fundamental changes in the fluxing schemes of the rezoning phase. This newest version of the code inherits all the droplet phase capabilities and physical sub-models of previous versions. The integration of the gas phase equations with moving solid boundaries continues to employ the successful arbitrary Lagrangian–Eulerian (ALE) methodology. Its new unstructured capability facilitates grid construction in complicated geometries and affords a higher degree of flexibility. The numerics of the code, emphasizing the new additions, are described. Various computational examples are performed demonstrating the new capabilities of the code.