Abstract:ρU 2 R = trailing-edge radius S = reference area, bc T = temperature t = model thickness u = streamwise velocity U = mean streamwise velocity x = streamwise axis y = wall-normal axis z = spanwise axis
“…The c p curve predicted by HyperFLOW on the medium grid matches reasonably well with the experimental data in Ref. 35. Figure 1(b) presents the c p results in mid-and high-blowing cases.…”
Section: Validation Casessupporting
confidence: 80%
“…The error of this estimation method for Cμ will increase as the jet intensifies.Figure 1.Comparison of the distributions with the experimental data in Ref. 35. (a) Low-blowing case, (b) mid- and high-blowing cases.…”
Section: Validation Of the Numerical Methodsmentioning
confidence: 94%
“…Comparison of the distributions with the experimental data in Ref. 35. (a) Low-blowing case, (b) mid- and high-blowing cases.…”
Section: Validation Of the Numerical Methodsmentioning
Over the last decade, many flight tests of the conventional/canard/flying-wing layout UAVs (unmanned aerial vehicle) have proven that the trailing-edge circulation control (CC) is an effective method to generate a significant rolling moment for the rolling control. However, the Coanda jet’s three-dimensional effects, especially the Coanda jet direction, on the design of UCAVs (unmanned combat air vehicle) have not been revealed and discussed clearly yet. In order to solve this problem, the effects of the Coanda jet direction on the swept wing’s aerodynamics and flow physics are investigated in detail in this paper. An in-house CFD(computational fluid dynamics) solver HyperFLOW with the Spalart–Allmaras for Rotation and Curvature turbulence model and the velocity inlet boundary has been validated by 2-D and 3-D CC cases and is used in this work. The research reveals that compared with the Coanda jet in the freestream direction (FJ jet), the Coanda jet perpendicular to the trailing edge (PJ jet) has a more significant impact on the aerodynamic loads and flow structures for swept wings, including increasing lift, drag, and nose-down moment, enhancing the wingtip vortex and weakening the thickness vortex. In contrast, the FJ jet performs better in improving the lift-to-drag ratio of swept wings. On a typical UCAV, the generalizability of the conclusion about the Coanda jet direction effects on the aerodynamic characteristics is verified. The current research gets an insight into the three-dimensional effects of the trailing-edge CC and provides solid support for implementing the CC technology into practical aircraft concepts.
“…The c p curve predicted by HyperFLOW on the medium grid matches reasonably well with the experimental data in Ref. 35. Figure 1(b) presents the c p results in mid-and high-blowing cases.…”
Section: Validation Casessupporting
confidence: 80%
“…The error of this estimation method for Cμ will increase as the jet intensifies.Figure 1.Comparison of the distributions with the experimental data in Ref. 35. (a) Low-blowing case, (b) mid- and high-blowing cases.…”
Section: Validation Of the Numerical Methodsmentioning
confidence: 94%
“…Comparison of the distributions with the experimental data in Ref. 35. (a) Low-blowing case, (b) mid- and high-blowing cases.…”
Section: Validation Of the Numerical Methodsmentioning
Over the last decade, many flight tests of the conventional/canard/flying-wing layout UAVs (unmanned aerial vehicle) have proven that the trailing-edge circulation control (CC) is an effective method to generate a significant rolling moment for the rolling control. However, the Coanda jet’s three-dimensional effects, especially the Coanda jet direction, on the design of UCAVs (unmanned combat air vehicle) have not been revealed and discussed clearly yet. In order to solve this problem, the effects of the Coanda jet direction on the swept wing’s aerodynamics and flow physics are investigated in detail in this paper. An in-house CFD(computational fluid dynamics) solver HyperFLOW with the Spalart–Allmaras for Rotation and Curvature turbulence model and the velocity inlet boundary has been validated by 2-D and 3-D CC cases and is used in this work. The research reveals that compared with the Coanda jet in the freestream direction (FJ jet), the Coanda jet perpendicular to the trailing edge (PJ jet) has a more significant impact on the aerodynamic loads and flow structures for swept wings, including increasing lift, drag, and nose-down moment, enhancing the wingtip vortex and weakening the thickness vortex. In contrast, the FJ jet performs better in improving the lift-to-drag ratio of swept wings. On a typical UCAV, the generalizability of the conclusion about the Coanda jet direction effects on the aerodynamic characteristics is verified. The current research gets an insight into the three-dimensional effects of the trailing-edge CC and provides solid support for implementing the CC technology into practical aircraft concepts.
“…This created a need for aerodynamic devices capable of creating substantial aerodynamic forces with limited surface area. AFC surfaces are suitable for such applications, as in the past they showed aerodynamic loadings far beyond limits for passive devices [4,5] Especially circulation control by steady tangential blowing in the boundary layer region seems promising for such applications. For design purposes of such devices, the precise value of vehicle drag is not of greatest importance, as much more important is the incremental drag prediction (di↵erence in drag force between configurations) as it is the parameter driving the design process.…”
Section: Introductionmentioning
confidence: 99%
“…Figure 1 shows the base-line geometry of a truck-trailer configuration. Augmented geometry was basically the same as the baseline geometry, with cylindrical Coanda surfaces based on the circulation control wing concept [4,5]. As the mentioned research program is ongoing, and the geometries are considered company's proprietary information, detailed geometries and AFC parameters are not provided in this article.…”
The study presents a computational study of a drag reduction device based on an active boundary layer control for a generic truck-trailer utility road vehicle. The conceptual device is in accordance with upcoming EU regulations regarding attachable aerodynamic devices for heavy utility vehicles. Design and principles of operation of the conceptual device are presented. The device is intended to increase decrease the trailer’s base drag coefficient by manipulation of the separated flow region behind the vehicle base. Results of a steady state Reynolds averaged analysis and Delayed Detached Eddy Simulation are presented to show the discrepancies of fluid flow patterns between baseline and augmented configuration as well as between mentioned CFD approaches. Results for drag reduction for baseline truck-trailer configuration and aerodynamically augmented configuration are presented.
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