How to calculate the force of fluid acting on the plane

1. The forces acting on the fluid are mass force and surface force. Because fluid can't bear concentrated force, it can only bear distributed force. Inertial force is not the external force that appears in the fluid particle e to the interaction between the fluid particle and other objects, but the virtual force that is supposed to be added to the fluid block with acceleration for the convenience of research and analysis.

2. F and f-prime do form a couple, but the couple of FA and FB can be balanced with M.

3. It means equivalent. In fact, this point of action does not exist, just as gravity has a point of action, which is also equivalent. In fact, it is the sum of all parts of gravity!

4. No, it is generally calculated according to the pressure of the liquid

5. It can be divided into three categories.
first, theoretical research methods. The motion process of fluid is mainly analyzed by Equation Derivation calculus, but it is difficult to solve the N-S equation. It should be said that it can not be solved temporarily, and it can be solved by constructing various fluid model equations.
Second, experimental fluid mechanics, In recent years, the development of numerical methods is more rapid and more popular field, through the computer to simulate the flow situation, the general representative software is fluent, Phoenix and so on

6. In mechanics of materials, the sign of shear stress is positive or negative when the micro element rotates clockwise, otherwise it is negative. In elasticity, for example, when the normal of the stress action plane of the shear stress TXY points to the positive direction of X, if the shear stress points to the positive direction of Y axis, it is positive, otherwise it is negative; Negative to positive, vice versa.

7. It can be divided into three categories.
first, theoretical research methods. The motion process of fluid is mainly analyzed by Equation Derivation calculus, but the solution of N-S equation is very difficult. It should be said that it can not be solved for the time being, and it can be solved by constructing various fluid model equations.
Second, experimental fluid mechanics, In recent years, the development of numerical methods is more rapid and more popular field, through the computer to simulate the flow situation, the general representative software is fluent, Phoenix and so on

8. Volume force

volume force is the force continuously distributed at each point in the component

mass force (volume force)

in a certain force field, all particles are subject to a force proportional to the mass, which is called mass force. The mass force is applied to every particle of fluid and is proportional to the mass of the fluid. For homogeneous fluid, it is also proportional to the volume of the fluid. The fluid in the gravity field by gravity, centrifugal force in the centrifugal force field are typical mass force

surface force (contact force or mechanical force)

the force acting on the outer surface of the studied fluid is proportional to the surface area. That is, the force exerted by the surrounding fluid on the surface of the separator. The surface force is proportional to the surface area of the fluid. The forces acting on any tiny surface in a fluid can be divided into two types: the forces perpendicular to the surface and the forces parallel to the surface. The former is pressure and the latter is shear. The static fluid is only affected by pressure, while the flowing fluid is affected by two kinds of surface forces at the same time.

9. This sentence comes from the definition of fluid. The difference between fluid and solid is that fluid cannot bear any shear stress. Once there is shear stress, it immediately deforms, so it is called fluid
as for the case that the shear stress is less than the force between molecules, this problem is not considered in general fluid mechanics, that is, no matter how the fluid can bear the shear stress.