动态的 压力动能，记为 q 或 Q，是单位体积流体的动能。其定义公式为 q = frac{1}{2} rho u^2[/latex]，其中 ρ 为局部流体密度，u 为流体速度。该量在流体动力学中至关重要，用于量化流体运动产生的压力。
动态压力
1738
- Daniel Bernoulli
（图片仅供参考）
The concept of dynamic pressure originates from the conservation of energy for a moving fluid. It represents the portion of the fluid’s total energy associated with its bulk motion. The formula [latex]q = \frac{1}{2} \rho u^2[/latex] can be derived by considering the kinetic energy ([latex]E_k = \frac{1}{2} m u^2[/latex]) of a small parcel of fluid with mass [latex]m[/latex] and volume [latex]V[/latex]. Since density [latex]\rho[/latex] is mass per unit volume ([latex]\rho = m/V[/latex]), the kinetic energy per unit volume is [latex]E_k/V = (\frac{1}{2} m u^2)/V = \frac{1}{2} (m/V) u^2 = \frac{1}{2} \rho u^2[/latex]. This result shows that dynamic pressure is not a pressure in the conventional sense of a normal force per unit area exerted by molecular collisions (which is static pressure). Instead, it is a scalar quantity with units of pressure (Pascals in SI units) that conveniently represents the kinetic energy density of the flow. This distinction is crucial; dynamic pressure cannot be measured directly by a standard pressure gauge oriented parallel to the flow. It can only be measured by bringing the fluid to a stop isentropically, converting its kinetic energy into a measurable pressure increase.
Historically, the groundwork was laid by Daniel Bernoulli in his 1738 work *Hydrodynamica*. While he formulated the overarching principle of energy conservation in fluids, the explicit isolation and naming of “dynamic pressure” as a distinct term became more common with the development of modern fluid dynamics and aerodynamics in the late 19th and early 20th centuries. Its utility lies in simplifying complex fluid dynamics equations. For instance, in many aerodynamic calculations, the forces are non-dimensionalized using dynamic pressure, which allows for the comparison of aerodynamic performance of different-sized objects at different speeds and in different fluids, as long as other parameters like the Reynolds number are matched. This makes it a cornerstone quantity for wind tunnel testing and computational fluid dynamics (CFD).
UNESCO Nomenclature: 2210
- 机械
类型
抽象系统
中断
基础
用法
广泛使用
前体
- 艾萨克-牛顿运动定律
- 动能的概念（[latex]E_k = frac{1}{2}mv^2[/latex]）
- 压力和密度的早期概念
- 能量守恒定律
应用程序
- 飞机设计（计算升力和阻力）
- 用于流量测量的文丘里流量计设计
- 用于空速测量的皮托管操作
- 天气预报（分析结构上的风荷载）
- 汽车设计（空气动力学优化）
- 土木工程（桥梁和建筑物的风荷载）
专利：
NA
潜在创新理念
Related to: dynamic pressure, fluid dynamics, kinetic energy, fluid density, fluid velocity, Bernoulli’s principle, pressure, aerodynamics, incompressible flow, fluid mechanics.
历史背景
动态压力
（如果日期未知或不相关，例如“流体力学”，则提供其显著出现的近似估计）
