Numerical prediction of the influence of uncertain inflow conditions in pipes by polynomial chaos

Abstract

Nearly all types of flow measurement devices installed in pipes are affected by the flow conditions at their inlet section, which can lead to measurement errors of several per cent. To evaluate the influence of uncertain inflow profiles on the flow field at different positions of the flow meter, a non-intrusive polynomial chaos approach is applied to simulations of turbulent pipe flow. This allows us to estimate the expected variations of the flow profiles as a function of the distance to the inlet of the pipe in an efficient way. The polynomial chaos approach shows reasonable convergence already for a small number of function evaluations. The results are validated by comparison with a quasi-Monte Carlo method and an exact solution, where available. The approximation error of the polynomial chaos method with 10 function evaluations is smaller than the one for the quasi-Monte Carlo method with 100 runs.

Keywords:

• non-intrusive generalised polynomial chaos
• uncertainty quantification
• computational fluid dynamics (CFD)
• pipe flow
• disturbed inflow profile

Acknowledgements

The authors would like to thank Dr Gudrun Wendt and Erkan Kublay (both from the Department ‘Liquid Flow’ at Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig) for sharing their measurement data as well as for fruitful discussions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. Experimental data obtained by Erkan Kublay at Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany

Additional information

Funding

This work was financially supported by EURAMET and the European Union within the EMRP research project NEW-04 ‘Novel mathematical and statistical approaches to uncertainty evaluation’.