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Assertion (A): When heat is transferred from a cylinder in cross flow to an air stream, the local heat transfer coefficient at the forwar dstagnation point is large.
Reason (R): Due to separation of the boundary layer eddiescontinuously sweep the surface close to the forward stagnation point.
Reason (R): Due to separation of the boundary layer eddiescontinuously sweep the surface close to the forward stagnation point.
- a)Both A and R are individually true and R is the correct explanation of A
- b)Both A and R are individually true but R is not the correct explanation of A
- c)A is true but R is false
- d)A is false but R is true
Correct answer is option 'B'. Can you explain this answer?
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Assertion (A): When heat is transferred from a cylinder in cross flow ...
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Assertion (A): When heat is transferred from a cylinder in cross flow ...
Assertion (A): When heat is transferred from a cylinder in cross flow to an air stream, the local heat transfer coefficient at the forward stagnation point is large.
Reason (R): Due to separation of the boundary layer, eddies continuously sweep the surface close to the forward stagnation point.
Explanation:
- The forward stagnation point on a cylinder is the point where the flow velocity is zero. This occurs at the front of the cylinder where the air stream impinges directly onto the surface.
- The heat transfer coefficient measures the rate of heat transfer per unit area per unit temperature difference between the surface and the surrounding fluid. A high heat transfer coefficient indicates a high rate of heat transfer.
- When a cylinder is placed in a cross flow of air, the boundary layer forms on the surface of the cylinder. The boundary layer is a thin layer of fluid adjacent to the surface where the velocity of the fluid gradually increases from zero to the free stream velocity.
- At the forward stagnation point, the boundary layer is highly turbulent due to the separation of the boundary layer. The separation occurs when the pressure on the surface of the cylinder is lower than the pressure of the free stream.
- The separation of the boundary layer leads to the formation of eddies or vortices close to the surface, which continuously sweep the surface near the forward stagnation point. These eddies enhance the heat transfer by increasing the mixing of the fluid near the surface.
- The continuous sweeping of the surface by the eddies helps in removing the stagnant fluid and bringing fresh fluid in contact with the surface. This enhances the convective heat transfer between the surface and the fluid.
- Therefore, both the assertion and the reason are individually true. The reason provides a correct explanation for the high local heat transfer coefficient at the forward stagnation point.
- Hence, the correct answer is option 'B': Both A and R are individually true, and R is the correct explanation of A.
Reason (R): Due to separation of the boundary layer, eddies continuously sweep the surface close to the forward stagnation point.
Explanation:
- The forward stagnation point on a cylinder is the point where the flow velocity is zero. This occurs at the front of the cylinder where the air stream impinges directly onto the surface.
- The heat transfer coefficient measures the rate of heat transfer per unit area per unit temperature difference between the surface and the surrounding fluid. A high heat transfer coefficient indicates a high rate of heat transfer.
- When a cylinder is placed in a cross flow of air, the boundary layer forms on the surface of the cylinder. The boundary layer is a thin layer of fluid adjacent to the surface where the velocity of the fluid gradually increases from zero to the free stream velocity.
- At the forward stagnation point, the boundary layer is highly turbulent due to the separation of the boundary layer. The separation occurs when the pressure on the surface of the cylinder is lower than the pressure of the free stream.
- The separation of the boundary layer leads to the formation of eddies or vortices close to the surface, which continuously sweep the surface near the forward stagnation point. These eddies enhance the heat transfer by increasing the mixing of the fluid near the surface.
- The continuous sweeping of the surface by the eddies helps in removing the stagnant fluid and bringing fresh fluid in contact with the surface. This enhances the convective heat transfer between the surface and the fluid.
- Therefore, both the assertion and the reason are individually true. The reason provides a correct explanation for the high local heat transfer coefficient at the forward stagnation point.
- Hence, the correct answer is option 'B': Both A and R are individually true, and R is the correct explanation of A.
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Assertion (A): When heat is transferred from a cylinder in cross flow to an air stream, the local heat transfer coefficient at the forwar dstagnation point is large.Reason (R): Due to separation of the boundary layer eddiescontinuously sweep the surface close to the forward stagnation point.a)Both A and R are individually true and R is the correct explanation of Ab)Both A and R are individually true but R is not the correct explanation of Ac)A is true but R is falsed)A is false but R is trueCorrect answer is option 'B'. Can you explain this answer?
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Assertion (A): When heat is transferred from a cylinder in cross flow to an air stream, the local heat transfer coefficient at the forwar dstagnation point is large.Reason (R): Due to separation of the boundary layer eddiescontinuously sweep the surface close to the forward stagnation point.a)Both A and R are individually true and R is the correct explanation of Ab)Both A and R are individually true but R is not the correct explanation of Ac)A is true but R is falsed)A is false but R is trueCorrect answer is option 'B'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about Assertion (A): When heat is transferred from a cylinder in cross flow to an air stream, the local heat transfer coefficient at the forwar dstagnation point is large.Reason (R): Due to separation of the boundary layer eddiescontinuously sweep the surface close to the forward stagnation point.a)Both A and R are individually true and R is the correct explanation of Ab)Both A and R are individually true but R is not the correct explanation of Ac)A is true but R is falsed)A is false but R is trueCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Assertion (A): When heat is transferred from a cylinder in cross flow to an air stream, the local heat transfer coefficient at the forwar dstagnation point is large.Reason (R): Due to separation of the boundary layer eddiescontinuously sweep the surface close to the forward stagnation point.a)Both A and R are individually true and R is the correct explanation of Ab)Both A and R are individually true but R is not the correct explanation of Ac)A is true but R is falsed)A is false but R is trueCorrect answer is option 'B'. Can you explain this answer?.
Assertion (A): When heat is transferred from a cylinder in cross flow to an air stream, the local heat transfer coefficient at the forwar dstagnation point is large.Reason (R): Due to separation of the boundary layer eddiescontinuously sweep the surface close to the forward stagnation point.a)Both A and R are individually true and R is the correct explanation of Ab)Both A and R are individually true but R is not the correct explanation of Ac)A is true but R is falsed)A is false but R is trueCorrect answer is option 'B'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about Assertion (A): When heat is transferred from a cylinder in cross flow to an air stream, the local heat transfer coefficient at the forwar dstagnation point is large.Reason (R): Due to separation of the boundary layer eddiescontinuously sweep the surface close to the forward stagnation point.a)Both A and R are individually true and R is the correct explanation of Ab)Both A and R are individually true but R is not the correct explanation of Ac)A is true but R is falsed)A is false but R is trueCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Assertion (A): When heat is transferred from a cylinder in cross flow to an air stream, the local heat transfer coefficient at the forwar dstagnation point is large.Reason (R): Due to separation of the boundary layer eddiescontinuously sweep the surface close to the forward stagnation point.a)Both A and R are individually true and R is the correct explanation of Ab)Both A and R are individually true but R is not the correct explanation of Ac)A is true but R is falsed)A is false but R is trueCorrect answer is option 'B'. Can you explain this answer?.
Solutions for Assertion (A): When heat is transferred from a cylinder in cross flow to an air stream, the local heat transfer coefficient at the forwar dstagnation point is large.Reason (R): Due to separation of the boundary layer eddiescontinuously sweep the surface close to the forward stagnation point.a)Both A and R are individually true and R is the correct explanation of Ab)Both A and R are individually true but R is not the correct explanation of Ac)A is true but R is falsed)A is false but R is trueCorrect answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for Mechanical Engineering.
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ample number of questions to practice Assertion (A): When heat is transferred from a cylinder in cross flow to an air stream, the local heat transfer coefficient at the forwar dstagnation point is large.Reason (R): Due to separation of the boundary layer eddiescontinuously sweep the surface close to the forward stagnation point.a)Both A and R are individually true and R is the correct explanation of Ab)Both A and R are individually true but R is not the correct explanation of Ac)A is true but R is falsed)A is false but R is trueCorrect answer is option 'B'. Can you explain this answer? tests, examples and also practice Mechanical Engineering tests.
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