scholarly journals Reduced order model for the lift coefficient of an airfoil equipped with extrados and/or trailing edge flexible flaps

2019 ◽  
Vol 180 ◽  
pp. 82-95 ◽  
Author(s):  
Chedhli Hafien ◽  
Talel Ben Mbarek
Author(s):  
Roelof Vos ◽  
Ron Barrett

One of the most compliant structures in aerospace applications that does not suffer from certification constraints is plain honeycomb. It is widely used in primary and secondary structure of FAR 23/25 certified aircraft. In this research, the compliant nature of this material is being exploited by inserting pouches in each of the honeycomb cells. Pressurizing these pouches results in a stiffening of the overall structure. By having an external (spring) force act on the honeycomb structure, this variable stiffness results in an overall deformation of the honeycomb. Strains in excess of 50% can be achieved through this mechanism without encountering the material (yield) limits. It can be shown that based on the maximum pressure that can be extracted from the High-Pressure Compressor in a typical jet engine, the energy density of pressure adaptive honeycomb is on the par with that of shape memory alloy, while exhibiting strains that are an order of magnitude larger at a transfer efficiency that is close to 1. The paper discusses the mechanics of pressure adaptive honeycomb and describes a simple reduced order model that can be used to simplify the geometric model in a finite element environment. The theory that underpins this reduced order model is shown to correlate well to experimental tests. In addition, a proof-of-concept application is presented where pressure-adaptive honeycomb is integrated over the aft 35% of a wing section. It is demonstrated that camber variations in excess of 5% can be generated by a pressure differential of 40kPa. Results of subsequent wind tunnel test show an increase in lift coefficient of 0.3 at a wind speed of 45kts across an angle of attack ranging from −6° to +20°.


Transmission Line model are an important role in the electrical power supply. Modeling of such system remains a challenge for simulations are necessary for designing and controlling modern power systems.In order to analyze the numerical approach for a benchmark collection Comprehensive of some needful real-world examples, which can be utilized to evaluate and compare mathematical approaches for model reduction. The approach is based on retaining the dominant modes of the system and truncation comparatively the less significant once.as the reduced order model has been derived from retaining the dominate modes of the large-scale stable system, the reduction preserves the stability. The strong demerit of the many MOR methods is that, the steady state values of the reduced order model does not match with the higher order systems. This drawback has been try to eliminated through the Different MOR method using sssMOR tools. This makes it possible for a new assessment of the error system Offered that the Observability Gramian of the original system has as soon as been thought about, an H∞ and H2 error bound can be calculated with minimal numerical effort for any minimized model attributable to The reduced order model (ROM) of a large-scale dynamical system is essential to effortlessness the study of the system utilizing approximation Algorithms. The response evaluation is considered in terms of response constraints and graphical assessments. the application of Approximation methods is offered for arising ROM of the large-scale LTI systems which consist of benchmark problems. The time response of approximated system, assessed by the proposed method, is also shown which is excellent matching of the response of original system when compared to the response of other existing approaches .


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