PhD Thesis - staffweb - University of Greenwich

PhD Thesis by John Ewer.take considerable time to develop due to the complexity and nature of the algorithms used.Furthermore such development is fraught with difficulty particularly for finding the empiricalmethods algorithm fine-tuning that give the best possible approximation to true physicalbehaviour for the target application area when no accurate numerical model exists. It is highlylikely that a new code development would get the design and data architecture correct for thedesired system but it is probable that the new development would have errors and omissions inthe empirical models and core algorithm formulation that could only be removed by extensiveresearch and iterative improvement. Research would need to be conducted into the algorithmsand empirical methods employed because various combinations of numerical techniques behavein very different ways even when disregarding the diversity of the target application areas. MostCFD codes are the combination and accumulation of many titbits of implementation knowledgefrom diverse information sources where such knowledge ranges in scope from the particularvalues used for a few constants in a particular application area to choices for more reliablesolution algorithm for the coupling of the solved variables. Validation of a new development isparticularly difficult because of the long development period before the system is in a state thatcan actually be used to run simulations and at such a stage any errors encountered would requireextensive modifications to the underlying software. As has been found in many previous newdevelopments there is unlikely to be trust in the development from potential users withoutextensive validation against existing software systems and experimental cases. The duplicationof effort for developing a new CFD code is particularly problematic for a limited durationproject. Generally a new code development would have no support from other developers sincethe information sources would be reference texts, journal papers and conference proceedingswith little access to numerical CFD software developers who have their own work loads.1.1.2 Add interactive functionality to an existing commercial CFD systemAt the beginning of this research a feasibility study was performed to ascertain if an existingcommercial CFD code should be used as the framework for this investigation. There were anumber of perceived problems with this approach.2-22