Relatively accurate calculation of 3-D control surface buzz in transonic flow

We were the first to apply unstructured dynamic mesh to relatively accurately calculating the effect of gap on 2-D control surface^[5]. Now, we apply such technique to relatively accurately calculating the effect of gap on 3-D control surface. Control surface buzz can only be roughly determined without considering the effect of gap. We explain in detail how to apply unstructured dynamic mesh to calculating 3-D control surface buzz. We add some pertinent remarks to listing the two topics of explanation: (1) method of calculation of unsteady aerodynamics; a finite volume algorithm based on center difference is used to solve the Euler equations; the full implicit dual-time scheme is adopted to treat the unsteady aerodynamic problem; (2) equation of motion of control surface and unstructured dynamic mesh technique; the subtopics are equation of motion of control surface and unstructured dynamic mesh technique; the control surface motion equation is marched by Runge-Kutta method in time domain; in order to take into account the effect of gap, the unstructured dynamic mesh technique is introduced to simulate the movement of the control surface; furthermore, we also propose some improvements to raise the capability of well-known unstructured dynamic mesh technique^[8]. Finally we took NASP (National AeroSpace Plane) wing with 3-D full-span control surface as numerical example. The results of calculation with our method show preliminarily fairly good agreement with test data.