The opaque coolant used in the removal machining processes has an inaccessibility problem for the form error in-process optical measurement. The water beam assisted approach should be one of the possible solutions for the problem. In this project, we propose to study the measurement process using the computational approach for better understanding of the process and for validating the models and settings. The experimental results and the Computational Fluid Dynamics (CFD) results are found close to each other. This gives us confidence in using the proposed CFD models and settings. The proposed new transparent window definition is suitable. The models and settings established include geometric model, mesh adaption model, domain settings, coolant concentration representation, expressions, boundary conditions, and CFX solver settings. The developed CFD models and settings will be useful in our further studies of the form error measurement method.