A prediction method for hydrodynamic load of seaplane with flow separation considered

考虑流动分离的水面载荷预报方法研究

¹ National Key Laboratory of Strength and Structure Integrity, Aircraft Strength Research Institute of China, Xi'an 710065, China
² School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China

Received: 16 August 2024

Abstract

During the early design phase of a seaplane, it is necessary to estimate the hydrodynamic load acting on the bottom structure of its fuselage. The flow separation is one of the important factors that makes it difficult to accurately analyse water load. The experimental or numerical methods often require a significant amount of time and cost, thus being difficult to meet the needs of the early design stage of the seaplane. Therefore, based on numerical and experimental analysis results, the liquid surface morphology after the wedge enters into water was simplified and approximated. A theoretical method was used to establish the relationship between the separation cavity angle and the inclined lift angle. The relationship was introduced into the semi-analytical method that considers the fictitious body continuation. The paper proposed a theoretical correction method for fast analysing the water entry slamming force after separation, which improved the ability to predict the slamming force in the early stage of separation at different inclined lift angles and water entry velocities.

摘要

水上飞机在设计阶段就需要对机身底部结构所受的水动力载荷进行估计, 而流动分离是导致难以准确分析水载荷的重要因素之一。采用实验或数值方法开展相关研究, 往往需要花费大量的时间和费用成本, 难以满足水上飞机早期设计阶段的需要。针对上述问题, 基于数值和实验分析结果对楔形体入水分离后的液面形态进行了简化和近似, 采用理论方法建立了分离后空腔角度和斜升角的关系式, 将其引入考虑虚拟物面的半解析方法中, 给出一种快速分析分离后入水砰击力的理论修正方法, 提高了预测不同斜升角和入水速度下分离初期砰击力的能力。