计算流体动力学（CFD）模型是一种计算机算法，它通过近似流体动力学方程来预测指定边界内流体的行为。这些模型已成为一种流行的工具，用于帮助优化设计，并提供流体行为的可视化表示。描述流体动力学的主要方程，纳维-斯托克斯方程，是在19世纪建立起来的。迄今为止，Navier-StokeSeq方程仅在非常特殊和简化的情况下求解。然而，随着计算机的发展，可以通过使用数值方法获得这些方程的近似值。 在基本流体力学中，对伯努利方程进行了修改，使其包含一个水头损失因子，该因子可解释湍流效应造成的压力损失。Darcy Weibasch或Hazen Williams方程可用于确定水头损失系数，并用于预测两点之间的压力损失。当实际的湍流效应和机理不需要完全建模时，这种方法通常足以解决大多数实际的通风工程问题。对于许多其他工程问题，这种方法是不够的，需要对湍流进行更详细的建模和理解。详细的湍流模型始于20世纪。 其中一个模型是“k-ε”湍流模型。该模型基于雷诺平均Navier-Stokes（RANS）方程，该方程是对原始Navier-Stokes方程的统计平均修正。奶牛饲养场需要适当的空气流动，以保持动物的舒适性，从而生产出质量更好的产品。在文献中，设计空气速度范围通常为5-7 mph（奶牛水平）。任何机械设计师在设计通风系统时都面临的一个挑战是确认空间内的彻底空气分布，因此，CFD建模是解决这一挑战的有用工具。传统上，风扇是用来供应空气的，但在奶牛场通常是不切实际的。 此外，设计者必须考虑在冬季的通风量减少和夏季的高流量，因为成本过高的制冷设备。本文介绍了在寒冷的加拿大天气下，为一个3900平方米（42000平方英尺）的奶牛场设计真实通风系统的实际建模。对CFD进行了分析，以比较以下设计方案，包括增加通风送风机和排风机的尺寸，单独使用排风机或送风机与送风机和排风机；且仅提供挡板、转移风扇或两者的组合。引用:佛罗里达州奥兰多2020年冬季会议论文

Computational Fluid Dynamics (CFD) models are computer algorithms which approximate fluid dynamics equations to predict the behavior of a fluidwithin a specified boundary. These models have become a popular tool to aid in the refinement and optimization of design, and to give a visualrepresentation of fluid behavior.The main equations that describe fluid dynamics, the Navier-Stokes Equations, were formulated in the 19th century. To this date, the Navier-Stokesequations have only been solved for very particular and simplified cases. However, with the evolution of computers, approximations to these equations canbe obtained by means of using numerical methods.In basic fluid mechanics, the Bernoulli Equation is modified to include a headloss factor which accounts for pressure losses due to turbulence effects.Darcy-Weibasch or Hazen Williams equations can be used to determine headloss factors and use it to predict pressure loss between two points. Thisapproach is often sufficient for most practical ventilation engineering problems when the actual turbulence effects and mechanism do not have to be fullymodeled. For many other engineering problems, this approach is insufficient, and a more detailed modelling and understanding of turbulence is required.Detailed turbulence models started being developed in the 20th century. One of these models is the “k-epsilon” turbulence model. The model is based onthe Reynolds Averaged Navier-Stokes (RANS) equations which are a statistically averaged modification of the original Navier-Stokes.Barns for dairy cows require proper air movement to maintain animal comfort to produce a better-quality product. In literature, the design air velocityrange is typically accepted as 5-7 mph at cow level. A challenge that any mechanical designer faces when engineering the ventilation system is to confirmthorough air distribution within the space, and as such, CFD modelling is a useful tool in solving this challenge. Traditionally, fans are used to supplyair, but it is often impractical in dairy barns. Moreover, the designer must consider reduced ventilation flows in the Winter and high flows in the Summerdue to cost prohibitive refrigeration equipment.This paper covers the actual modeling to design a real ventilation system for a 3,900 m2 (42,000 ft2) dairy farm in cold Canadian weather. CFD isanalyzed to compare the following design alternatives including increasing size of the ventilation supply and exhaust fans, using exhaust or supply fansonly vs both supply and exhaust fans; and provision of baffles only, transfer fans only or a combination of both.