Nozzle geometry for liquids (general practice): Which overall shape is a nozzle generally made in for subsonic liquid jets and efficient discharge?

Introduction / Context:
Nozzles convert pressure energy into kinetic energy. Their geometry depends on the working fluid and target Mach number. For water and most engineering liquid applications (subsonic), practical nozzles are convergent to accelerate the flow and form a coherent jet for power transmission (e.g., Pelton wheels), cutting, or cleaning.

Given Data / Assumptions:

• Incompressible liquid (water-like), subsonic regime.
• Applications requiring high exit velocity and compact jet.
• Negligible compressibility effects compared with gases.

Concept / Approach:
For incompressible or low-Mach flows, continuity and Bernoulli imply that reducing area increases velocity and reduces static pressure toward the outlet. A convergent profile assists smooth acceleration with minimal separation. Convergent–divergent (de Laval) profiles are used for compressible gases to produce supersonic jets; not typically necessary for liquids.

Step-by-Step Solution:

Verification / Alternative check:
Hydraulic machinery references list convergent nozzles for water jets; C-D nozzles are reserved for gas dynamics when choking and supersonic expansion are required.

Why Other Options Are Wrong:

• Cylindrical: Does not accelerate the flow appreciably; large losses at entry/exit.
• Divergent: Decelerates subsonic flow; opposite of desired effect.
• Convergent–divergent: Appropriate for compressible gas flows aiming for M > 1, not typical water jets.

Common Pitfalls:
Generalizing gas-dynamics nozzle shapes to liquids; overlooking separation risk from abrupt contractions.

Final Answer:
convergent shape