The basic form of fluid equation is ρ*(ρ*u)*u+ρ* g*(ρ*h)=0.
ρ represents fluid density, u represents fluid velocity, g represents gravity acceleration, and h represents fluid height.
This equation describes the motion state of fluid, from which we can draw some important conclusions. Firstly, the equation shows that the motion of fluid is related to the density, velocity and height of fluid. When the density and velocity of the fluid change, the motion state of the fluid will also change. In addition, the acceleration of gravity will also affect the movement of fluid, for example, under the action of gravity, the fluid flows downward and forms precipitation.
Fluid equations can also describe many other types of fluid motion, such as turbulence and laminar flow. Turbulence refers to the fluid flow state with variable speed and direction, which usually appears in the boundary layer of fluid movement. Laminar flow refers to the flow state in which the velocity and direction of fluid remain constant, which usually appears in the internal area of fluid movement.
Fluid equation technology;
1. Simplify the equation: For some simple fluid motions, we can try to simplify the fluid equation, such as simplifying a three-dimensional problem into a two-dimensional problem or a one-dimensional problem, thus reducing the amount of calculation and difficulty.
2. Choose a suitable numerical calculation method: We need to choose a suitable numerical calculation method for different fluid equations and problems, such as the finite element method for steady-state problems and the finite difference method for transient problems.
3. Use turbulence model: For complicated fluid movements such as turbulence, we often need to use turbulence model to simplify fluid equations, such as k-ε model and LES model. These models can effectively simulate turbulent motion and improve calculation efficiency and accuracy.
4. Select appropriate boundary conditions: boundary conditions have great influence on the solution of fluid equations, so we need to select appropriate boundary conditions, such as given velocity, pressure and other physical quantities.
5. Consider viscosity and heat transfer of fluid: viscosity and heat transfer of fluid will affect the solution of fluid equation, so it is necessary to consider the influence of these factors on fluid motion.