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Current state-of-the-art in automotive computational aerodynamics relies on either multi-block structured grids or homogeneous unstructured tetra or hexa meshes. This paper presents a novel approach of unstructured solution-adaptive grids and a generalized tree-based Adaptive Cartesian/Prismatic (ACP) grid concept for automotive aerodynamic applications. The proposed concept resolves several problems which plague tetrahedral grids such as boundary layer grid cell aspect ratio or large grid count. ACP employs unstructured adaptive layer of prisms (or quads in 2D) near solid walls intersected with an adaptive tree-based Cartesian mesh in the rest of the computational space. The prismatic layer resolves the viscous wall layer with high aspect ratio mesh whereas the Cartesian tree mesh provides the smooth grid transition, allows grid coarsening and offers the best support for accurate numerical schemes.

This study is a joint development project between Chrysler Corporation and CFD Research Corporation. The objective of this investigation was to develop a 3D computational flow and heat transfer model for a vehicle windshield de-icing process. The windshield clearing process is a 3D transient, multi-medium, multi-phase heat exchange phenomenon in connection with the air flow distribution in the passenger compartment. The transient windshield de-icing analysis employed conjugate heat transfer methodology and enthalpy method to simulate the velocity distribution near the windshield inside surface, and the time progression of ice-melting pattern on the windshield outside surface. The comparison between the computed results and measured data showed very reasonable agreement, which demonstrated that the developed analysis tool is capable of simulating the vehicle cold room de-icing tests.

A numerical study of an automotive windshield ice-clearing was successfully accomplished. The windshield clearing process is a 3D transient, multi-medium, multi-phase heat exchange phenomenon in connection with the air flow distribution in the passenger compartment. The transient windshield clearing analysis employed conjugate heat transfer and enthalpy methods to simulate the ice-melting pattern and the melting duration. This study is a joint project between Chrysler Corporation and CFD Research Corporation. A Chrysler prototype windshield and test vehicle were utilized. The meshing was done using ICEM/CFD package by Control Data Corporation (CDC). A seamless data transfer was achieved by developing an interface between ICEM/CFD and CFD-ACE. The analysis of air flow, conjugate heat transfer, and weather clearing was performed using the multi-domain CFD-ACE code developed by CFD Research Corporation (CFDRC).