Oral cavity flow distribution and pressure drop in balaenid whales feeding: a theoretical analysis
Oral cavity flow distribution and pressure drop in balaenid whales feeding: a theoretical analysis
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鲸鱼进食时口腔流量分布和压降：理论分析
DOI：
10.1088/1748-3190/ab6fb8
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发表时间：
2020
影响因子：
3.4
通讯作者：
Hu Dean
中科院分区：
文献类型：
--
作者：
Zhu Yawei;Yang Gang;Zhuang Chen;Li Changran;Hu Dean
鲸鱼作为连续的公羊滤食性动物，可以通过鲸须有效地将猎物与水分离。鲸鱼的摄食过程极其复杂，其中口腔内的流量分布和压降起着重要作用。本文基于质量守恒、动量守恒和压降方程，考虑惯性项和摩擦项，建立了鲸鱼口腔速度和压力耦合的理论模型。采用逐段计算的离散方法求解理论模型。讨论了四个关键参数的影响，即过滤面积与入口面积之比（S）、入口雷诺数（Rein）、边缘层形成的多孔介质的厚度与渗透率之比（ψ）以及口内沿舌（APT通道）与沿唇部（APL通道）的前后管宽度比（H）。结果表明，对于给定情况，流量分布和压降均随流动方向呈现增加趋势。不同情况下，当S较小、Rein较小、φ较大时，会出现良好的流态，口咽部附近的流速更平滑，排水效果更好，分流和过滤效果更好，能量效率更高。然而，对于较小的 H 值，需要牺牲一些能量效率来实现额外的平均横向流动，从而产生更好的分流和过滤。本文的研究为高效仿生过滤器的设计提供参考。
Balaenid whales, as continuous ram filter feeders, can efficiently separate prey from water by baleen. The feeding process of balaenid whales is extremely complex, in which the flow distribution and pressure drop in the oral cavity play a significant role. In this paper, a theoretical model coupled with oral cavity velocity and pressure in balaenid whales is established based on mass conservation, momentum conservation and pressure drop equations, considering both the inertial and the friction terms. A discrete method with section-by-section calculation is adopted to solve the theoretical model. The effects of four crucial parameters, i.e. the ratio of filtration area to inlet area (S), the Reynolds number of entrance (Rein), the ratio of thickness to permeability of the porous media formed by the fringe layer (ϕ) and the width ratio of the anteroposterior canal within the mouth along the tongue (APT channel) to that along the lip (APL channel) (H) are discussed. The results show that, for a given case, the flow distribution and the pressure drop both show increasing trends with the flow direction. For different cases, when S is small, Rein is small and ϕ is large, a good flow pattern emerges with a smoother flow speed near the oropharynx, better drainage, better shunting and filtration, and higher energy efficiency. However, for smaller values of H, some energy efficiency is sacrificed to achieve additional average transverse flow in order to produce better shunting and filtration. The research in this paper provides a reference for the design of high-efficiency bionic filters.