Experimental models for validating technology updating gatherer database
The accuracy required is usually stated as part of the design process.The accuracy observed from the CFD simulation varies according to the character of the quantity, and so, it is not possible to state an accuracy or error band that applies to all quantities obtained from the CFD simulation.The levels of uncertainties and errors are determined through verification assessment and validation assessment.Verification assessment determines if the programming and computational implementation of the conceptual model is correct.Levels of credibility may vary according to the information required. CFD provides details on the entire flow field not possible with experimental methods. Corrections to experimental observations can be provided by CFD at a higher accuracy than existing with the CFD method.The application of CFD for design and analysis may be catagorized into three levels according to increased levels of required accuracy: 1) provide qualitative information, 2) provide incremental quantities, and 3) provide absolute quantities. This is useful in understanding on a qualitative level the behavior of the flow field. This is due to cancellation of part of the error when taking the differences.The E is the error associated with the quantity P obtained from the CFD simulation.
Verification and validation examines the errors in the code and simulation results.
There is professional disagreement on exact procedures for verification and validation of CFD simulations. CFD is a complex technology involving strongly coupled non-linear partial differential equations which attempt to computationally model theoretical and experimental models in a discrete domain of complex geometric shape.
A detailed assessment of errors and uncertainties has to concern itself with the three roots of CFD: theory, experiment, and computation.
It examines the mathematics in the models through comparison to exact analytical results.
Verification assessment examines for computer programming errors.
However, as the code continues to develop, verification and validation should continue.