A study of formative and continuous models for umbrella water curtain based on wall-attaching jets

In this paper, models are established to assess the characteristics of an umbrella water curtain, and two properties on formation and continuity are investigated theoretically. According to flow process of the jets, three computational steps, wall-attaching formation process, wall-attaching flow process and free flow process, are designed to analyze the characteristics. Based on the geometry establishing of an umbrella water curtain, three typical factors, namely, jet velocity, incident angle and wall inclination, are modeled in the first two computational steps to analyze the formative characteristics, and numerical investigation is carried out carefully based on the wall-attaching jets. To analyze the continuous characteristics, a length model on the free flow process is proposed, and an improved Wave-KH model combining with the primary break-up theory are presented to improve its predictive precision. Numerical investigation considering wall length else is also discussed in detail and the biggest factor affecting the continuous performance is revealed. Simulations and experiments are provided to verify the validity of these models, the contrastive results show that models can describe the formative and continuous characteristics more accurate, and models also provide a theoretical basis for fluidic parameter design on an umbrella curtain.