hydraulics 2
211. What is the wetted perimeter in pressurized flows?
Coincides with the geometric perimeter
212. How is flow rate typically measured?
In volume or mass per unit time
213. What is the volumetric flow rate?
The volume of fluid passing through a cross-section per unit time
214. What is the mass flow rate?
The mass of fluid passing through a cross-section per unit time
215. What is the uniqueness condition in fluid dynamics problem solving?
Geometric, physical, initial, and boundary conditions are considered
216. What characterizes a real fluid?
It offers resistance to shearing forces
217. In a viscous fluid, what causes shear stresses?
Frictional forces caused by motion
218. What role do the Navier-Stokes equations play in fluid dynamics?
They are fundamental in the hydrodynamics of viscous fluids
219. Have analytical solutions been found for the Navier-Stokes equations?
Only for a very limited range of special cases
220. What are the characteristics of an ideal fluid?
No resistance to shearing forces and only normal forces
221. How are uniqueness conditions defined in fluid dynamics problems?
Geometric, physical, initial, and boundary conditions together
222. In the context of fluid motion, what does divergence measure?
How much the incoming and outgoing flow from a small neighborhood of a point diverges
223. What does the hydraulic radius represent?
The ratio of wetted cross-sectional area to wetted perimeter
224. What is the continuity equation related to in fluid dynamics?
Conservation of momentum and incompressibility
225. What are some uniqueness conditions that need to be imposed when solving fluid dynamics problems?
Geometric, physical, initial, and boundary conditions
226. How are mass, weight, and volumetric flow rates different from each other?
They measure different aspects of fluid flow
227. In a viscous fluid, what leads to the presence of shear stresses?
Frictional forces when the fluid is in motion
228. What properties characterize hydrodynamic pressure in a non-viscous fluid?
Properties identical to hydrostatic pressure
229. How do streamlines behave in steady motion?
They remain constant throughout the motion
230. In steady motion, how do streamlines and trajectories relate to each other?
They coincide when the motion is steady
231. What differentiates steady flow from unsteady flow?
Steady flow has constant motion parameters at any point
232. In unsteady flow, how do streamlines behave?
They change continuously over time
233. What does the term "trajectory" mean in fluid motion?
The route followed by a specific fluid particle
234. Why do streamlines not intersect?
Velocity vectors have different directions at intersections
235. What does the term "stream tube" refer to in fluid dynamics?
A tubular surface created by connecting streamlines around a closed contour
236. How are flow rate and flow area related?
Flow rate depends on flow area, with varying velocities
237. What does the fundamental equation of hydrostatics primarily relate to in a stationary liquid?
The conservation of energy
238. What does Bernoulli's equation establish the relationship between in a moving ideal fluid?
Velocity and pressure
239. According to the law of conservation of energy, what does the change in kinetic energy during displacement equal?
The sum of all external and internal work
240. What is the work of internal forces in an ideal incompressible fluid?
Zero
241. Which external forces contribute to the work done on a selected volume of fluid?
Pressure forces and gravitational force
242. What is the specific potential energy of a liquid particle's position referred to per unit weight of the liquid in Bernoulli's equation?
Geometric height
243. What remains constant along a streamline in the case of steady flow of an ideal incompressible fluid?
Total head
244. How does the hydraulic head relate to the total specific mechanical energy along a streamline?
It is equal to the total specific mechanical energy.
245. What is the interpretation of Bernoulli's equation from a physical standpoint?
The law of conservation of energy for a moving fluid
246. What does the total specific mechanical energy along an elementary stream of an ideal fluid remain?
A constant value
247. In Bernoulli's equation, what does the term "P/γ" represent?
Specific potential energy due to pressure
248. From a geometric perspective, what does Bernoulli's equation represent in any cross-section of an elementary stream of an ideal fluid?
The sum of three heights: geometric, piezometric, and velocity
249. What happens to pressure when the cross-sectional area of the stream increases in an ideal fluid flow?
Pressure increases
250. In a real fluid, what causes losses of mechanical energy due to friction within the liquid and against the channel walls?
Viscosity