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Synthetic Jet flow Control CFD and Characterization

Periodic Reporting for period 2 - SYNJET3C (Synthetic Jet flow Control CFD and Characterization)

Reporting period: 2019-04-01 to 2021-03-31

In aim at decreasing the consumption of the aircrafts, by reduction of the drag aerodynamic losses, the objectif is to limit the flow separation on the wings. In this context, Active Flow Control (AFC) based on air blowing actuator could be applied to wing junction, leading edge and rudders, as well as wing junctions with engines. Among this technology, the Synthetic Jet Actuators (SJA) are a solution without net mass flux. As the technology is now not well understood yet, SYNJET3C project aims at increase the knowledge of SJA in quiescent air condition and cross flow conditions by accurate modelling based on correlation with Wind Tunnel Test (WTT).

In the current situation of climate change and environmental preoccupation, the reduction of aircraft consumption is an important question for society.

The first objective of SYNJET3C is to characterize an existing SJA designed by Fraunhofer ENAS and actuated by a piezo-membrane.
The understanding and modelling of the behavior of this SJA will allow to define the performance to reach with the next generation of SJA.
A new prototype will be designed, manufactured and tested.
The project results have shown that technology of SJA has been improved very significantly toward much higher output speed flow compared to former state of the art which was lower than 130m/s. Both small scale SJA and large Scale SJA were tested at much high level of performances.
• Small scale SJA – 200m/s flow speed achieved (See pictures "Prototype of small scale SJA" and "Small scale SJA fluid speed test results")
• Large scale SJA – 300m/s flow speed achieved (See pictures "Prototype of large scale SJA" and "Large scale SJA fluid speed test results")

The progress achieved was possible thanks to the advanced modelling approach which has been developed in this project, and improved based on correlations using wind tunnel tests.
As described on picture "Model VS Test Results", the system modelling developped all along the project is working well.
The project has allowed for the first time to characterise SJA technology from electrical efficiency point of view. The following good results, leading to efficient use in future flight applications, have been measured:
• High electrical efficiency about 60%
• High output thrust mechanical power of 20 W, achieved with 30 W electrical power
• High power factor about 0,8 leading to high efficiency as well on SJA drive electronic

Two publications have been presented at conferences:
• AEC2020: “On going progress in flow control actuator and associated drive electronics”.
• ACTUATOR2020: “High power synthetic jet actuators”

The project web page and publications are available on CEDRAT TECHNOLOGIES (CTEC), see the URL below.
In the first period of the project, the partners have contributed to increase the understanding of the SJA behavior in quiescent air condition via measurements and modelling. For the end of the project a similar work was done in cross flow condition which is a real progress compared to the previous projects as ASPIC and VIPER. Then the design of a SJA with low mass will be a very interesting mechanism for the mass and consumption reduction of the aircrafts if the system reaches performance high enough in terms of output jet velocity and flowrate at the nozzle.

The second part of the project was to design, manufacture and test a new optimized SJA. The final results on the different prototypes are higher than expeted in term of fluid speed. One additionnal key aspect is the measurement of the efficiency for the first time. Indeed, this kind of data was never measured by the past.

The success of the project could give to the European project partners an interesting place in the aircrafts market. Then, by an equal access of all European companies to this technology managed by CTEC, the impact for the European economy could be large.
Large scale SJA fluid speed test results
Prototype of small scale SJA
Model VS Test Results
Small scale SJA fluid speed test results
Prototype of large scale SJA