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Missile Trajectory Models, Aerodynamic Derivatives, Dynamic Coefficients and Missile Transfer Functions
Published in Qi Zaikang, Lin Defu, Design of Guidance and Control Systems for Tactical Missiles, 2019
In general, if the position of the center of gravity is approximately 50% of the missile length from the head of the missile, we expect that the center of pressure of the missile body will be placed approximately 52—55% of the missile length from the head of the missile. It can be seen that at subsonic and low supersonic speeds,subsonic and low supersonic speeds the position of the center of pressure is farther ahead than that in the case of a high Mach number. In addition, at low speeds, the position of the center of pressure is greatly influenced by the angle of attack. This is mainly due to the fact that the center of pressure component of the missile body without wing and fins often moves backward as the angle of attack increases, but the center of pressure components of the control surface and the missile wing do not change much. Unfortunately, the position of the center of pressure is also a function of the angle of attack plane angle λ that characterizes the roll direction of the total angle of attack αT plane.
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
In addition to knowing the lift and drag for an airfoil, it is often necessary to know the location where these forces act. This location, the center of pressure, is important is determining the moments that tend to pitch the nose of the airplane up or down. Such information is often given in terms of a moment coefficient, CM=MqoSc
Equations of motion
Published in Mohammad H. Sadraey, Aircraft Performance, 2017
We can integrate pressure and shear stress over the entire surface of the lifting surface (e.g., wing) to have one resultant force. The location of this resultant force (see Figure 2.3) is referred to as the center of pressure (cp). The location of this center depends on aircraft speed and the airfoil’s angle of attack. In subsonic speeds, as the angle of attack is increased, the center of pressure moves forward (below stall angle). At supersonic speeds, the center of pressure moves toward the mid chord, since the airfoil is often biconvex or bi-wedge.
Numerical simulation of subsonic flow around oscillating airfoil based on the Navier–Stokes equations
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Dmytro. Redchyts, Unai Fernandez-Gamiz, Oleg Polevoy, Svitlana Moiseienko, Koldo Portal-Porras
Five stages can be distinguished for this flow regime. The angle of attack of the airfoil exceeds the static stall angle (Fig. 6a(1)). The flow changes the direction of movement in the boundary layer.Beginning of flow stall (Fig. 4a and Fig. 6a(2)). A further increase in the angle of attack leads to a dynamic separation of the vortices from the leading edge of the airfoil. This angle is greater than the static stall angle since unsteady effects delay the stall and thereby increase the dynamic value of the lift coefficient compared to the static one.Vortices are transferred along the chord with approximately one-quarter of the free stream velocity (Fig. 4b-d and Fig. 6a (2–3)). This results in an increase in the lift coefficient. The center of pressure shifts from the airfoil leading edge to the trailing edge.A sharp drop in the lift coefficient (Fig. 4e-f, Fig. 5a-б, and Fig. 6a (3–4)). After the vortex reaches the trailing edge, a global separation of the flow from the upper surface occurs. The vortex generated by the trailing edge of the airfoil interacts with the main vortex (Fig. 5 a). The direction of rotation is different. After the beginning of the downward motion of the airfoil, the pressure peak near the airfoil leading edge drops sharply.Flow reattachment (Fig. 5c-e and Fig. 6a (5)) starts near the leading edge. The position of the attachment point shifts toward the airfoil trailing edge when the angle of attack becomes sufficiently small.
The design of the center of pressure apparatus with demonstration
Published in Cogent Engineering, 2020
Nuralhuda A. Jasim, Mohammed S. Shamkhi
In general term, the center of pressure is located below centroid since pressure increase with depth. The determination of the center of pressure can be performed by equating the moments of the resultant and distributed forces about any arbitrary axis. The fluid pressure distributed over its surface can be achieved by several examples such as a plate exposed to the fluid.