Accuracy analysis of a physical scale model using the example of an asymmetric orifice

For a throttled surge tank of a high-head power plant in Austria the local head loss for an asymmetric orifice has to be quantified and optimized. The physical scale model tests (1:25) of nine different orifices are used as a validation experiment for 3D-numerical simulations (ANSYS-CFX). The increased requirements for the comparison of these two model assumptions lead to an extended accuracy analysis of the hydraulic model test. Based on Bernoulli[U+05F3]s equation, theoretical error terms are added to the measured variables (differential pressure and discharge) and thus the measurement accuracy of different instrumentations was tested. The verification of the scale test is based on long-term observation. These tests include the measurement of the vibration of the scale model and an investigation of the temporal offset between the different types of measurement instruments. The results are also examined with the help of a sensitivity analysis.