End of term4
What is the Pouseuille formula used for in the laminar flow regime in circular pipes?
Velocity distribution
According to the Kolbrug and White formula, where is it applicable in turbulent flow?
Rough pipes with natural roughness in the subquadratic regio
What is the equivalent roughness (Δ_e) in the Prandtl-Nikuradze formula for smooth pipes with Δ_e/d = 0?
Zero
In the laminar regime, what are losses per length proportional to?
Flow rate raised to the power of one
What is the main factor influencing the coefficient of local losses (ξ)?
Reynolds number (Re)
How are local resistances in a pipeline considered in approximate calculations?
As mutually influencing
What is the condition for the principle of adding losses to be valid for local resistances?
Distance greater than the flow stabilization distance
What does the Borda equation determine for abrupt expansion in a pipe?
Head loss
What is the effect of abrupt constriction on head losses compared to abrupt expansion?
Lower head losses
In the case of an abrupt constriction, what does the coefficient ξ depend on?
Cross-sectional areas
What does the curvature of the flow on the concave side of the inner surface of the pipe result in?
Higher pressure
What is the purpose of the equivalent length of the local resistance in hydraulic calculations?
. To simplify calculations
What factors does the coefficient of local losses (ξ) depend on?
Shape of the local resistance, Reynolds number, and surface roughness
How are losses per length proportional in the turbulent regime?
Flow rate raised to the power of one
In hydraulic reference materials, to what velocity head is the coefficient ξ usually related?
Velocity head after the local resistance
How is the validity of the principle of adding losses affected by local resistances in close proximity?
Invalidated
What determines the applicability of the principle of adding losses in the design of pump stations?
Distance between local resistances
In the Borda equation, what does v represent?
Lost velocity
At what angle in a diffuser does the loss coefficient reach a maximum?
70°
What is the advisable transition instead of using diffusers with an angle of 2θ > 40°?
Abrupt expansion
How are head losses in the case of abrupt constriction compared to abrupt expansion?
Lower
In the case of an abrupt constriction, what causes head losses?
Compression of the jet
What phenomenon in local resistances results from the flow detaching from the walls and moving as a jet?
Separation zones
What is the coefficient of local losses (ξ) for a symmetrical tee typically dependent on?
Reynolds number
What is the purpose of introducing the concept of equivalent length of the pipeline in hydraulic
calculations?
To simplify calculations
What does the Reynolds number influence in the coefficients of local losses (ξ)?
Velocity head
What is the equivalent roughness (Δₑ) defined as in hydraulic reference books?
Grainy roughness
What is the purpose of the coefficient of local losses (ξ)?
To relate head losses to the velocity head
How does the head loss in a diffuser change with increasing expansion angle (α)?
Increases
What is the primary purpose of the Borda equation in hydraulic calculations?
To estimate head losses in abrupt expansion