(SEM IV) THEORY EXAMINATION 2022-23 HYDRAULIC ENGINEERING & MACHINES

SECTION A – What These Questions Are About

Section A contains 10 basic conceptual questions, each carrying 2 marks.
They check your understanding of fundamental terms, definitions, and formula-based concepts in hydraulics and hydraulic machines.

Topics covered in Section A questions include:
• Air vessels in reciprocating pumps → Used to reduce acceleration head and to make flow uniform.
• Manning’s equation → Fundamental formula for uniform flow in open channels.
• Jet ratio of Pelton turbine → Ratio of pitch diameter to jet diameter.
• Specific energy in open channel flow → Energy relative to channel bottom.
• Force exerted by a jet → Basic jet impact calculation using momentum.
• NDL and CDL on mild slope → Normal Depth Line vs. Critical Depth Line relationship.
• Dynamic equation of GVF → Governing differential equation of gradually varied flow.
• Types of surges → Hydraulic transient phenomena (positive, negative, etc.).
• Hydraulic jump → Sudden transition from supercritical to subcritical flow.
• Parts of Pelton turbine → Buckets, runner, nozzle, spear, casing, etc.

Purpose of Section A:
To ensure you know definitions, physical meanings, governing formulas, and basic hydraulic behavior.

SECTION B – What These Questions Are About

Section B requires solving any three numerical or derivation-type questions, each carrying 10 marks.
These questions involve long derivations, numerical calculations, and conceptual explanations.

Topics covered in Section B questions include:
• Most economical trapezoidal channel → Derivation of conditions for maximum discharge/minimum perimeter.
• Chezy’s equation and assumptions → Uniform flow formula and theoretical basis.
• Specific energy calculation & critical depth discussion → Open channel critical state interpretation.
• Hydraulic jump derivation → Relation between sequent depths and Froude number.
• Impact of jet on curved plate → Calculation of force using momentum change.
• Types of efficiencies of turbines → Hydraulic, mechanical, overall efficiency and their relationships.

Purpose of Section B:
To test your ability to derive hydraulic relations, apply energy and momentum equations, and interpret open channel/turbine behavior.

SECTION C – What These Questions Are About

Section C contains deeper, analytically complex problems.
You must attempt any one question from each pair.

Topics included:

• Most economical rectangular channel → Conditions where hydraulic radius is maximized.
• Design of trapezoidal channel (best hydraulic efficiency) → Use Manning’s formula to find slope and dimensions.
• Gradually Varied Flow (GVF) profile → Compute water depth profile and sketch its behavior.
• Critical depth due to hump or contraction → Use specific energy concepts to determine geometric changes.

Purpose of Section C (Part 1 & 2):
To evaluate your understanding of open channel design, GVF behavior, and hydraulic efficiency.

SECTION C – Further Numerical Applications

Next part of Section C asks for hydraulic jump analysis or turbine/pump design.

Topics included:

• Types of hydraulic jumps → Based on Froude number and channel location.
• Sequent depth & energy loss → Calculations for hydraulic jump in rectangular channels.
• Construction and working of centrifugal pump → Impeller, casing, suction pipe, delivery pipe.
• Single-stage vs. multi-stage pumps → Operating principle and applications.
• Characteristics curves of rotodynamic pumps → Head vs. discharge, power vs. discharge, efficiency curves.

Purpose:
To test both conceptual understanding and practical machinery knowledge.

SECTION D – Final Part of Section C

The last set of questions involve Pelton wheel design and turbine characteristics.

Topics included:

• Design of Pelton wheel → Based on head, power, rotational speed, efficiency and jet velocity.
• Specific speed ranges → For Kaplan, Francis and Pelton turbines.
• Draft tube & its use → Recover kinetic head and increase turbine efficiency.
• Types of draft tubes → Straight, elbow, conical, Moody spreading tubes etc.

Purpose:
To evaluate your understanding of hydraulic turbines, specific speed concept, and turbine design components.