Discrete Vortex Method Combined with the Singularity Method for Numerical Analysis of Flow Past Arbitrary Two-Dimensional Bluff Body

Abstract: At present, computational wind engineering (CWE) is an important means to solve problem of wind engineering in addition to theory analysis and experiment with the rapid development of CWE.CWE has a wide prospect.In this paper, beginning with the simple introduction of all sorts of primal methods for computational fluid dynamics (CFD), the conception of discrete vortex method (DVM) is imported. At the same time ,the advantage and disadvantage of all methods under high Renold number are discussed . After concentrated introduction of the conception of DVM, a simplified numerical model is proposed under high Renold number which is a DVM model combined singularity method. In this model, the vortex element is shed from the separation point directly, the Rankine model is choose when the singularity of vortex core is being solved, and when vortex elements run into the boundary of body, they are omitted. At last, the least squares procedure is used to meet the condition of boundary.In this paper ,the formula of the force acted on the body is deduced .getting the aerodynamics derivation and the method of calculating the critical wind velocity of flutter are discussed, and the progress of solution for the coupling question of bluff bodies and fluid is provided .At the end of this paper, a numerical program is made. The flow of typical bluff body i.e. square cylinder under different angel is simulated . The figure of vortex element's displacement and streamline are got. At the same time ,the curve of aerodynamics force with time is got too. The result is in good agreement with the literature's . The flow past a flat plate undergoing a harmonic oscillate is discussed to test the method of getting the aerodynamics derivative and the numerical procedure .It is unfortunate that the result is not good agreement with the theory. More test of theprogram on the flow past a bridge section is not satisfactory with contrasting to the result of experiment. The analysis of numerical examples proves that the numerical procedure of this paper can be used to qualitative research, but cannot get accurate aerodynamics force when applying to engineering . The dominating reason of error may be the shedding of nascent vortex…
Key words: discrete vortex; singularity method; aerodynamics derivative; separate point

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