In this post, I have shared a list of interview questions for the subject of Fluid Mechanics. Fluid mechanics is one of the most important subjects from an industrial point of view. Learning these interviews will not only help you prepare well for the interview but will also help you to learn concepts well.
Fluid Mechanics Interview Questions
1. What are the most common states of matter?
Ans. Solid and Fluid are the two important states of matter from the point of view of chemical industries.
2. What is the difference between solid and fluid?
Ans. Solid can resist deformation until a range and will break or change shape after it. But fluid won't resist deformation no matter how small it is. This is what differentiates solids from fluids.
3. What is fluid?
Ans. Fluid is a substance that can't resist distortion permanently no matter how low shear stress. This means how the small shear force you apply on a layer of fluid, will start moving. And won't stop until you stop applying shear stress.
4. What is included in fluids?
Ans. Fluid includes both liquids and gases because both follow the definitions of fluids.
5. How we can differentiate liquids from gases?
Ans. Liquid molecules are nearer to each other than in the gas phase. So there is why there are more cohesive forces in two molecules in liquid form. This is why liquids have a higher density than gases.
6. What is mass?
Ans. Mass represents the amount of matter. Mass can't be directly measured, so it is measured by another similar term weight. The unit of mass is Kg, Grams, or lb (pronounced as a pound).
7. What is weight?
Ans. Weight is the multiplication of mass of matter and gravitational constant. Weight is often used for the measurement of mass. Weight measuring scales are widely used to measure the mass of matter. The unit of weight is Newton which unit of force.
6. What is density?
Ans. Density is the ratio of the mass of material per unit volume. Unit of density is kg/m^3 or gm/cc (here cc means cubic centimeter which means cm^3).
7. What is a specific volume?
Ans. Specific volume means the volume of the material per unit mass. (Tip. When there is specifically written before any quantity that means that quantity per unit mass. Exception. Specific gravity and specific weight)
8. What is specific weight?
Ans. Specific weight is the ratio of weight per unit volume. The unit of specific weight is Newton/m^3.
9. What is specific gravity?
Ans. Specific gravity is the ratio of the density of matter to the density of standardized material. This standardized material can be water or air. For the calculations of specific gravity for liquids, water is used as a standardized liquid and for gases, air is used.
10. What is viscosity?
Ans. The viscosity of property of the fluid resists the flow of fluids. Fluids with low viscosity flow easily. For example, water having low viscosity flows very easily, and honey having higher viscosity stops after flowing to a small distance.
11. What is the rheological behavior of fluid?
Ans. The rheological behavior of fluid means how the rate of shear changes concerning shear stress.
12. Classification of fluids according to rheological behaviors.
Ans. Newtonian fluids and Non-Newtonian Fluids are the major classifications of fluid according to rheological behaviors. Non-Newtonian fluids are Bingham plastic, pseudoplastic, dilatant, thixotropic, and rheopectic.
13. What is a Newtonian fluid?
Ans. Newtonian fluids are fluids that follow Newton's law of viscosity.
14. What is Newton's law of viscosity?
Ans. Newton's law of viscosity states that for Newtonian fluids rate of shear is proportional to shear stress applied on the fluid.
15. What are Non-Newtonian fluids?
Ans. Non-Newtonian fluids are fluids that don't follow Newton's law of viscosity.
16. What is aspirant viscosity?
Ans. Apparent viscosity is the ratio of shear stress and rate of shear. The apparent viscosity of Newtonian fluids is constant. For Non-Newtonian fluids this apparent viscosity changes concerning shear rate.
17. What is dynamic viscosity?
Ans. Dynamic viscosity is a property of the material. Dynamic viscosity shows us how the fluid will resist the flow. The unit of dynamic viscosity is Pa*Sec or Poise.
18. What is kinematics viscosity?
Ans. Kinematic viscosity is the ratio of dynamic viscosity to the density of the fluid. This is also the property of the fluid which is how the momentum will diffuse in the fluid. The unit of kinematic viscosity is m^2/sec or stokes.
19. What is surface tension?
Ans. Surface tension is a property of a material that shows a comparison of cohesive force (attractive force between molecules of the same material) and adhesive force (attractive force between molecules of different material) of any material.
20. Application of surface tension.
Ans. The surface tension of any material shows how the material will wet the surface. Materials with low surface tension will wet the surface well. Water has high surface tension, so it wet the surface well and Mercury with high surface tension will not wet the surface well.
So in this post, I have shared twenty interview questions about fluid mechanics from chapter introduction to the fluid. In future posts, I will share other fluid mechanics interview questions.
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