Uncertainty quantification integrated to CFD modeling of synthetic jet actuators

The Point-Collocation Non-intrusive Polynomial Chaos (NIPC) method has been applied to a stochastic synthetic jet actuator problem used as one of the test cases in the CFDVAL2004 workshop to demonstrate the integration of computationally efficient uncertainty quantification to the high-fidelity CFD modeling of synthetic jet actuators. The test case included the simulation of an actuator generating a synthetic jet issued into quiescent air. The Point-Collocation NIPC method is used to quantify the uncertainty in the long-time averaged u and v-velocities at several locations in the flow field due to the uniformly distributed uncertainty introduced in the amplitude and frequency of the oscillation of the piezo-electric membrane. Fifth-order NIPC expansions were used to obtain the uncertainty information, which showed that the variation in the v-velocity is high in the region directly above the jet slot and the variation in the u-velocity is maximum in the region immediately adjacent to the slot. Even with a ±5% variation in the amplitude and frequency, the long-time averaged u and v-velocity profiles could not match the experimental measurements at y=0.1 mm above the slot indicating that the discrepancy may be due to other uncertainty sources in CFD and/or due to the measurement errors.