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Power effects aerodynamics for a regional turboprop

Periodic Reporting for period 1 - PERTURB (Power effects aerodynamics for a regional turboprop)

Reporting period: 2019-05-01 to 2020-01-31

Load Control Alleviation (LCA) in future regional turboprop aircraft designs will allow excessive gust and manoeuvre loads to be avoided, therefore enabling enhanced structural wing designs, eventually leading to considerable weight savings, lower fuel burn and reduced environmental impact. The PERTURB project is one of a series of projects in Clean Sky 2 which inform the flight demonstrator FTB2 in the Regional Aircraft domain. This demonstrator will evaluate new aerodynamic devices and concepts for LCA, which might appear on a future regional turboprop. PERTURB will use a combination of CFD and wind-tunnel testing to generate a trusted high-fidelity aerodynamic characterisation of both the propeller aerodynamics and the aircraft configuration aerodynamics in terms of propeller slipstream influence on wings, nacelles and flaps. As well as providing data to inform the flight trials of FTB2, PERTURB will also develop a methodology for determining accurate aerodynamic data in the future using combined CFD and wind-tunnel test data.
CFD-ready geometry has been created for the POLITE model and a mesh generated for the cruise case, power-off. Results have been generated power-off and compared with the RUAG wind-tunnel data from the ReLOAD project.

As the TM could not supply a database for propeller modelling for use with the actuator disk in steady RANS modelling, this data has been generated from 2D aerofoil CFD codes.

Due to the non-compliance of the POLITE model for power-on testing in ONERA F1, options for recovery plans have been investigated. A technical way forward has now been agreed with the JU/TM and this plan now requires costing.
There are three main innovations in PERTURB:
> The coupling of a RANS capability with a Vortex Particle Method (VPM). This overall methodology, which gives superior modelling of vortices in a RANS context at little extra cost, was only conceived in the last three years and has only been demonstrated to date on very simple test cases. PERTURB will allow the methodology to be demonstrated on propeller tip vortices and flap-end vortices. It is judged that PERTURB will elevate the capability to TRL5-6.
> VFM for propeller modelling using CFD. Although Variable Fidelity Modelling has been used in simpler settings, it has not been used for installed propeller modelling. As using unsteady RANS for propeller simulation is very expensive, VFM will allow high-fidelity data at the URANS level to be generated at reduced cost, due to its combination with low-fidelity modelling using steady RANS with an actuator disk. There are good prospects for this type of process being integrated into future design studies.
> VFM for merging CFD and WTT data. The use of VFM as a tool for fusing together CFD and wind-tunnel test data will be demonstrated in the more complex setting of propeller aerodynamics. Prospects are for reduced costs of aerodynamic data generation and reduced uncertainty, and hence risk, in using data.
CFD cruise geometry for POLITE wind-tunnel model