Small aspect ratios and sweep-back both have a powerful influence in preventing the shock-induced separation. In order to prevent shock-induced separation, it is necessary to move the borderline AB upward and to the right, so that a greater range of flight conditions may be obtained. The line BB′ marks the border of leading-edge separated flow, from the shock-induced separated flow. B is extended to the left in order to indicate the onset of separation effects when the critical separation is of some low-speed type. Onset boundary and subdivision of regime for separation effects Īt point A, which represents zero lift, the shock is at the rear section, and at point B the shock moves to the leading edge. The joint strengths, failure modes involved chord face failure, chord sidewall failure, and local buckling failure of brace, as well as the load–deformation curves of stainless steel tubular joints were all summarized in Ref.FIG. The validity range of these geometric parameters defined in the tests and parametric study were purposely designed beyond those given in the current design specifications for carbon steel and stainless steel structures. The effects of critical influential factors on the strength and behavior of cold-formed stainless steel tubular joints were evaluated, which include the brace width to chord width ratio ( β=b 1/ b 0), brace thickness to chord thickness ratio ( τ=t 1/ t 0), chord width to chord thickness ratio (2 γ=b 0/ t 0), brace width to brace thickness ratio ( b 1/ t 1), chord depth to chord thickness ratio ( h 0/ t 0), brace depth to brace thickness ratio ( h 1/ t 1), chord depth to chord width ratio ( h 0/ b 0), brace depth to brace width ratio ( h 1/ b 1), and the compressive chord preload ( N p). Ben Young, in Finite Element Analysis and Design of Metal Structures, 2014 8.2.3 Influential Factors Read moreĭesign Examples of Metal Tubular ConnectionsĮhab Ellobody. The impinging-shear-layer instability emerges at a certain Reynolds number between 200 and 400. However, in a certain range of d/h of the same mode, no irregularity appears in the course of vortex shedding independently of d/h, whereas irregularity grows with d/h for Re=1000. Thus, the flow at Re=400 is governed by the impinging-shear-layer instability in agreement with our previous experiment conducted at Re=1000. (2)Īt Re=400, the Strouhal number based on depth d, St(d), increases stepwise in a similar way to the flow at Re=1000. The flow is not governed by the impinging-shear-layer instability, but by the interaction between the shear- layers separated from the trailing edges. The main results of this study can be summarized as follows: (1)Īt Re=200, the Strouhal number based on the height h, St(h), is nearly constant. The chord-to-thickness ratio of a plate, d/h, ranged from 3 to 10 and the values of the Reynolds number based on the plate's thickness were 200 and 400. That table also includes multiple deformations coming from the combination of different devices.įlows around flat plates with square leading and trailing edges were analyzed numerically by direct integration of the Navier-Stokes equations using the finite-difference method. 32 compares the airfoil performance for the A3_10–A3_12 morphed shapes of Table 6. All of the morphing states listed in Table 6 (thus, including the clean airfoil) are numerically characterized and the relative look-up tables are computed by using a Euler/Boundary layer code. The airfoil geometries resulting from the separate application of the morphing devices are depicted in Fig. In particular, the airfoil nose is drooped by 10°, 15°, and 20° three different rotations are set for the trailing edge (2.5°, 5°, and 10°) the trailing edge plate is extended 60%, 75%, or 90% of its length which is based on 20% of the local chord. The applied deformations, which are summarized in Table 6, originate from literature review. Among the airfoils specified in Table 3, the airfoil with 12% thickness-to-chord ratio is selected for the application of the morphing techniques described in paragraph 4.5.3.
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