AKTU Hydraulic Engineering & Machines · Important Questions 2026Source: ryzenstudy.com PYQs
BCE403 Hydraulic Engineering & Machines Important Questions 2026 (AKTU)
Repeat analysis + most-asked questions, unit-wise
What we did: built from all 4 AKTU Hydraulic Engineering & Machines papers (2021-22–2024-25): 94 questions grouped into 60 distinct questions, 20 of which were asked in more than one paper.
- of marks were repeat questions
- 40%
- of marks were repeat questions
- questions asked in 2+ papers
- 20
- questions asked in 2+ papers
- papers analysed (2021-22–2024-25)
- 4
- papers analysed (2021-22–2024-25)
- units, mapped to current syllabus
- 5
- units, mapped to current syllabus
How much of the paper repeats?
- Repeats are real: when we checked each newer BCE403 paper against the papers before it, on average 40% of its marks were questions already asked in an earlier paper.
- 2023-24 paper: 41% of marks were repeats (6 of 8 repeated questions were in our top list).
- 2024-25 paper: 40% of marks were repeats (6 of 9 repeated questions were in our top list).
- Topic weightage is a guide, not a guarantee: our Tier 1 + Tier 2 topics covered 48% of the next paper's marks — picking the same number of topics at random would have covered about 44%.
Across 10 subjects and 23 papers we tested, 43% of marks repeated earlier questions on average.
1.Unit-wise most-asked questions
Ranked by how many papers asked them, then by how recently. Click a paper to open it.
Unit 1: Introduction
23% of past marks| Question | Asked |
|---|---|
| What is the most efficient channel section and why? | Asked 2× |
| A flow of 5.0 m3/s is passing at a depth of 1.50 m through a rectangular channel of width 2.50 m. What is the specific energy of the flow? What is the value of the alternate depth to the existing depth? | Asked 2× |
| An irrigation channel of trapezoidal section has side slope of 1.5 horizontal to 1 vertical and bed slope of 1 in 4000. The channel has to pass a discharge of 15 m3/s and is to be lined, for which the value of N in the operating formula is 0.012. Find the dimensions of the most economical section of the channel. | Asked 2× |
| State the conditions under which the rectangular section of an open channel will be most economical. Derive these conditions. | Asked 2× |
Unit 2: Energy-Depth relationship
22% of past marks| Question | Asked |
|---|---|
| Uniform flow occurs at a depth of 1.5 m in a long rectangular channel 3 m wide and laid to a slope of 0.0009. If Manning's n = 0.015, calculate (a) maximum height of hump on the floor to produce critical depth, (b) the width of contraction which will produce critical depth without increasing the upstream depth of flow. | Asked 3× |
| Derive the equations of GVF for a wide rectangular channel using (a) Manning's formula, (b) Chezy's formula. | Asked 2× |
| The width of contraction which will produce critical depth without increasing the upstream depth of flow (see original paper for the full question). | Asked 2× |
| Show that in a rectangular channel maximum discharge occurs when the flow is critical for a given value of specific energy. | Asked 1× |
Unit 3: Rapidly varied flow
18% of past marks| Question | Asked |
|---|---|
| Write the types of surges. | Asked 3× |
| Find the sequent depth ratio and energy loss for a hydraulic jump in a horizontal rectangular channel. | Asked 3× |
| What is the principle of hydraulic jump? | Asked 3× |
| Explain the difference between deep and shallow water waves. | Asked 2× |
Unit 4: Pumps
18% of past marks| Question | Asked |
|---|---|
| With a neat diagram find out the force of jet on a stationary vertical plate. | Asked 2× |
| Explain with a neat sketch the construction details and working principles of a centrifugal pump. | Asked 2× |
| What is NPSH of a centrifugal pump? How is it related to cavitation in the pump? 7 marks2024-25 Q2(e) | Asked 1× |
| Compare centrifugal and reciprocating pumps with examples. 7 marks2024-25 Q4(a) | Asked 1× |
Unit 5:
19% of past marks| Question | Asked |
|---|---|
| A Pelton wheel turbine is to be designed for the following specifications: shaft power = 11,775 kW, head = 400 m, speed = 750 rpm, overall efficiency = 86%, jet diameter to wheel diameter ratio is not to exceed one sixth (1/6). Find wheel diameter and jet diameter. | Asked 3× |
| Draw neat sketches of various shapes of draft tubes. Also explain the theory of draft tube. | Asked 3× |
| Explain the working of a Pelton turbine with a neat diagram. | Asked 2× |
| Define jet ratio in case of a Pelton turbine. | Asked 2× |
2.Topic weightage: which topics carry the marks
Blue = Tier 1 + Tier 2 (topics that carried ~80% of past marks). Grey = the rest. It shows where marks have gone, not a promise of what comes next.
Flow over humps · U2
8.6% (cum 9%)
Most efficient channel section · U1
8.6% (cum 17%)
Jump elements in rectangular channel · U3
8% (cum 25%)
Chezy and Manning equations · U1
6.8% (cum 32%)
Pelton turbine · U5
6.7% (cum 39%)
Francis and Kaplan turbines · U5
5.4% (cum 44%)
GVF classification and profiles · U2
4.5% (cum 49%)
Jet on stationary plates · U4
3.9% (cum 53%)
Specific energy and force · U1
3.5% (cum 56%)
Centrifugal pump operation · U4
3.3% (cum 59%)
Specific energy applications · U2
3.1% (cum 62%)
Open channel surges · U3
3% (cum 65%)
Impulse and reaction turbines · U5
2.9% (cum 68%)
Critical depth and flow regimes · U1
2.8% (cum 71%)
Pump velocity triangles · U4
2.8% (cum 74%)
Types of hydraulic jump · U3
2.7% (cum 77%)
Channel width contractions · U2
2.5% (cum 79%)
Multistaging and pump selection · U4
2.4% (cum 82%)
GVF equation · U2
2% (cum 84%)
Deep and shallow water waves · U3
1.9% (cum 85%)
Reciprocating pumps · U4
1.8% (cum 87%)
Hydraulic jump principle · U3
1.7% (cum 89%)
Turbine cavitation · U5
1.5% (cum 90%)
Pump cavitation and NPSH · U4
1.4% (cum 92%)
Jet on moving plates · U4
1.3% (cum 93%)
Unit quantities and similarity · U5
1.3% (cum 94%)
Specific speed · U5
1.3% (cum 96%)
GVF integration methods · U2
1.2% (cum 97%)
Impulse momentum equation · U4
1.2% (cum 98%)
Free surface flow concepts · U1
1.2% (cum 99%)
Energy dissipaters · U3
0.7% (cum 100%)
| Topic | Papers | Share |
|---|---|---|
| Flow over humps · Unit 2 · Tier 1 | 3/4 | 8.6% |
| Most efficient channel section · Unit 1 · Tier 1 | 4/4 | 8.6% |
| Jump elements in rectangular channel · Unit 3 · Tier 1 | 3/4 | 8% |
| Chezy and Manning equations · Unit 1 · Tier 1 | 3/4 | 6.8% |
| Pelton turbine · Unit 5 · Tier 1 | 4/4 | 6.7% |
| Francis and Kaplan turbines · Unit 5 · Tier 1 | 3/4 | 5.4% |
| GVF classification and profiles · Unit 2 · Tier 1 | 3/4 | 4.5% |
| Jet on stationary plates · Unit 4 · Tier 1 | 2/4 | 3.9% |
| Specific energy and force · Unit 1 · Tier 2 | 3/4 | 3.5% |
| Centrifugal pump operation · Unit 4 · Tier 2 | 2/4 | 3.3% |
| Specific energy applications · Unit 2 · Tier 2 | 2/4 | 3.1% |
| Open channel surges · Unit 3 · Tier 2 | 4/4 | 3% |
| Impulse and reaction turbines · Unit 5 · Tier 2 | 2/4 | 2.9% |
| Critical depth and flow regimes · Unit 1 · Tier 2 | 2/4 | 2.8% |
| Pump velocity triangles · Unit 4 · Tier 2 | 1/4 | 2.8% |
| Types of hydraulic jump · Unit 3 · Tier 2 | 2/4 | 2.7% |
| Channel width contractions · Unit 2 · Tier 2 | 2/4 | 2.5% |
| Multistaging and pump selection · Unit 4 · Tier 2 | 2/4 | 2.4% |
| GVF equation · Unit 2 · Tier 3 | 2/4 | 2% |
| Deep and shallow water waves · Unit 3 · Tier 3 | 2/4 | 1.9% |
| Reciprocating pumps · Unit 4 · Tier 3 | 2/4 | 1.8% |
| Hydraulic jump principle · Unit 3 · Tier 3 | 3/4 | 1.7% |
| Turbine cavitation · Unit 5 · Tier 3 | 1/4 | 1.5% |
| Pump cavitation and NPSH · Unit 4 · Tier 3 | 1/4 | 1.4% |
| Jet on moving plates · Unit 4 · Tier 3 | 1/4 | 1.3% |
| Unit quantities and similarity · Unit 5 · Tier 3 | 1/4 | 1.3% |
| Specific speed · Unit 5 · Tier 3 | 1/4 | 1.3% |
| GVF integration methods · Unit 2 · Tier 3 | 1/4 | 1.2% |
| Impulse momentum equation · Unit 4 · Tier 3 | 1/4 | 1.2% |
| Free surface flow concepts · Unit 1 · Tier 3 | 2/4 | 1.2% |
| Energy dissipaters · Unit 3 · Tier 3 | 1/4 | 0.7% |
3.Paper pattern (2024-25)
| Section | Questions | Rule |
|---|---|---|
| A | 7 × 2 marks | Attempt all |
| B | 5 × 7 marks | Attempt any 3 |
| C | 11 × 7 marks | Attempt any 1 |
4.In the syllabus, never asked yet
Low priority, but read them once — a new paper can always start here.
- Energy and momentum principles · U1
- Velocity distribution · U1
- Celerity of gravity wave · U3
- Pump performance curves · U4
- Turbine characteristic curves · U5
5.Study order
- 1Flow over humps (Unit 2, Tier 1)
- 2Most efficient channel section (Unit 1, Tier 1)
- 3Jump elements in rectangular channel (Unit 3, Tier 1)
- 4Chezy and Manning equations (Unit 1, Tier 1)
- 5Pelton turbine (Unit 5, Tier 1)
- 6Francis and Kaplan turbines (Unit 5, Tier 1)
- 7GVF classification and profiles (Unit 2, Tier 1)
- 8Jet on stationary plates (Unit 4, Tier 1)
- 9Specific energy and force (Unit 1, Tier 2)
- 10Centrifugal pump operation (Unit 4, Tier 2)
- 11Specific energy applications (Unit 2, Tier 2)
- 12Open channel surges (Unit 3, Tier 2)
- 13Impulse and reaction turbines (Unit 5, Tier 2)
- 14Critical depth and flow regimes (Unit 1, Tier 2)
- 15Pump velocity triangles (Unit 4, Tier 2)
- 16Types of hydraulic jump (Unit 3, Tier 2)
- 17Channel width contractions (Unit 2, Tier 2)
- 18Multistaging and pump selection (Unit 4, Tier 2)
FAQ
Which units of BCE403 carry the most marks?
Unit 1 (Introduction, 23% of past marks) and Unit 2 (Energy-Depth relationship, 22% of past marks).
Do AKTU Hydraulic Engineering & Machines questions repeat?
Yes. On average 40% of the marks in each newer BCE403 paper came from questions already asked in an earlier paper, and 20 questions have appeared in more than one paper.
How is this list made?
Every question from the 4 papers (2021-22–2024-25) was mapped to the current AKTU syllabus and grouped with the same question from other years. Questions are ranked by how many papers they appeared in, then by how recently.
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Note: this is based on past AKTU papers, not a guarantee. Questions are mapped to the current syllabus; topics that are no longer in the syllabus are left out.