特种筒形桅杆风压试验

锥形筒形桅杆是一种新型桅杆 ,由于其结构的特点 ,风载可能对它产生较大的威胁。通过四面锥状筒型桅杆的风洞试验 ,研究了桅杆模型在不同风向下 ,在雷诺数 1 .7× 1 0 5 Re 7.8× 1 0 5的范围中 ,其周向与轴向的表面压力分布 ,给出了桅杆模型表面压力系数沿周向与轴向的变化规律 ,并作了分析 ,阐明了其与风向、雷诺数之间的关系。通过桅杆模型表面压力的周向积分 ,得到了模型的升力与阻力 ,导出升力系数与阻力系数 ,并分析了二者随雷诺数及风向的变化规律。试验分析结果表明 :压力系数沿轴向的分布不均匀 ,靠近桅杆模型的中间部位 ,压力系数较大 ;在桅杆模型的两端 ,压力系数较小。压力系数沿周向的分布与风向有关 ,在迎风面上 ,压力系数最大 ,在背风面上 ,压力系数最小。升力系数与阻力系数也与风向密切相关 ,并且随着风向的变化 ,有较大的变化。在筒型桅杆设计中 ,应充分考虑到风向变化所引起的风载变化。

Experiment of Wind Pressure on Cone Shaped Mast

The cone shaped mast is a new type mast designed for ship special demands. As a result of its special structure, wind pressure may cause damage. A four side cone shaped mast model was tested in a wind tunnel. Pressure on the mast model under different wind direction and among the Re range of 1.7E5 to 7.8E5 was measured. The pressure distributions in peripheral and axial directions were obtained. By integrating the pressure, the model's lifting and resistance coefficients were obtained. The experimental results indicate: (1) The distribution of pressure coefficient is not uniform along the axial direction, with the relatively high value near the middle position and relatively low valne near the two edges. (2) The distribution of pressure coefficient in periphery is related to the wind direction, with the high value on the facing side and low value on the lee side. (3) The lifting coefficient and resistance ooefficient are also related to the wind direction. Therefore, the pressure variation due to wind direction should be considered in the design of the cone shaped mast.