Mechanical Engineering Exam > Mechanical Engineering Questions > Drag on cylinders and spheres decreases when ...
Start Learning for Free
Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 since
- a)Flow separation occurs due to transition to turbulence
- b)Flow separation is delayed due to onset of turbulence
- c)Flow separation is advanced due to transition to turbulence
- d)Flow reattachment occurs
Correct answer is option 'D'. Can you explain this answer?
| FREE This question is part of | Download PDF Attempt this Test |
Verified Answer
Drag on cylinders and spheres decreases when the Reynolds number isin ...
Ans. (d) In the region of 2 × 105 (Reynolds number), the boundary layer on the cylinders and sphere begins to become unstable and thus boundary layer is said
to reattach and the separation point moves back along the cylinder. Due to flow reattachment, a pressure recovery takes place over the back side and thus the
drag force decreases.
to reattach and the separation point moves back along the cylinder. Due to flow reattachment, a pressure recovery takes place over the back side and thus the
drag force decreases.
Most Upvoted Answer
Drag on cylinders and spheres decreases when the Reynolds number isin ...
Explanation:
Reynolds Number:
- Reynolds number is a dimensionless quantity that is used to predict flow patterns in different fluid flow situations.
- It is defined as the ratio of inertial forces to viscous forces in a fluid flow.
Effects of Reynolds Number on Drag:
- At low Reynolds numbers, the flow is laminar, and drag on a cylindrical or spherical object is dominated by viscous forces.
- As Reynolds number increases, the flow transitions from laminar to turbulent, resulting in a decrease in drag force.
Reattachment of Flow:
- When flow separation occurs around a cylinder or sphere, it creates a wake region behind the object where the flow is separated from the surface.
- As the Reynolds number increases, the flow is more likely to reattach after separation, leading to a decrease in drag force.
- This reattachment of flow is facilitated by the onset of turbulence, which helps in energizing the flow and reducing the size of the wake region.
Therefore, the correct option is option 'D' - Flow reattachment occurs, as the decrease in drag on cylinders and spheres at Reynolds numbers around 2 x 10^5 is due to the reattachment of flow facilitated by the transition to turbulence.
Reynolds Number:
- Reynolds number is a dimensionless quantity that is used to predict flow patterns in different fluid flow situations.
- It is defined as the ratio of inertial forces to viscous forces in a fluid flow.
Effects of Reynolds Number on Drag:
- At low Reynolds numbers, the flow is laminar, and drag on a cylindrical or spherical object is dominated by viscous forces.
- As Reynolds number increases, the flow transitions from laminar to turbulent, resulting in a decrease in drag force.
Reattachment of Flow:
- When flow separation occurs around a cylinder or sphere, it creates a wake region behind the object where the flow is separated from the surface.
- As the Reynolds number increases, the flow is more likely to reattach after separation, leading to a decrease in drag force.
- This reattachment of flow is facilitated by the onset of turbulence, which helps in energizing the flow and reducing the size of the wake region.
Therefore, the correct option is option 'D' - Flow reattachment occurs, as the decrease in drag on cylinders and spheres at Reynolds numbers around 2 x 10^5 is due to the reattachment of flow facilitated by the transition to turbulence.
Attention Mechanical Engineering Students!
To make sure you are not studying endlessly, EduRev has designed Mechanical Engineering study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Mechanical Engineering.
|
Explore Courses for Mechanical Engineering exam
|
|
Top Courses for Mechanical EngineeringView all
Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. Can you explain this answer?
Question Description
Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. 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 Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. 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 Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. Can you explain this answer?.
Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. 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 Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. 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 Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. Can you explain this answer?.
Solutions for Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for Mechanical Engineering.
Download more important topics, notes, lectures and mock test series for Mechanical Engineering Exam by signing up for free.
Here you can find the meaning of Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of
Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. Can you explain this answer?, a detailed solution for Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. Can you explain this answer? has been provided alongside types of Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice Drag on cylinders and spheres decreases when the Reynolds number isin the region of 2 × 105 sincea)Flow separation occurs due to transition to turbulenceb)Flow separation is delayed due to onset of turbulencec)Flow separation is advanced due to transition to turbulenced)Flow reattachment occursCorrect answer is option 'D'. Can you explain this answer? tests, examples and also practice Mechanical Engineering tests.
|
|
Explore Courses for Mechanical Engineering exam
|
|
Suggested Free Tests
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
|
© EduRev
|
Education Revolution
|
Follow Us
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup