# The Reynolds number, $R e$ is defined as $\frac{U_{\infty} L}{v}$ where $L$ is the length scale for a flow, $U_{\infty}$ is its reference velocity and $v$ is the coefficient of kinematic viscosity. In the laminar boundary layer approximation, comparison of the dimensions of the convection term $u \frac{\partial u}{\partial x}$ and the viscous term v $\frac{\partial^{2} u}{\partial x^{2}}$ leads to the following relation between the boundary layer thickness $\delta$ and $R e$ : (A) $\delta \propto \sqrt{R e}$ (B) $\delta \propto 1 / \sqrt{R e}$ (C) $\delta \propto R e$ (D) $\delta \propto 1 / R e$

## Question ID - 155717 :- The Reynolds number, $R e$ is defined as $\frac{U_{\infty} L}{v}$ where $L$ is the length scale for a flow, $U_{\infty}$ is its reference velocity and $v$ is the coefficient of kinematic viscosity. In the laminar boundary layer approximation, comparison of the dimensions of the convection term $u \frac{\partial u}{\partial x}$ and the viscous term v $\frac{\partial^{2} u}{\partial x^{2}}$ leads to the following relation between the boundary layer thickness $\delta$ and $R e$ : (A) $\delta \propto \sqrt{R e}$ (B) $\delta \propto 1 / \sqrt{R e}$ (C) $\delta \propto R e$ (D) $\delta \propto 1 / R e$

1 Answer
5876 Votes
3537

Answer Key : (B) -

(B) $\delta \propto 1 / \sqrt{R e}$

Next Question :

Isentropic efficiencies of an aircraft engine operating at typical subsonic cruise conditions with the following components - intake, compressor, turbine and nozzle - are denoted by $\eta_{i}, \eta_{c}, \eta_{t}$ and $\eta_{n},$ respectively. Which one of the following is correct?
(A) $\eta_{i}<\eta_{c}<\eta_{t}<\eta_{n}$
(B) $\eta_{t}<\eta_{i}<\eta_{c}<\eta_{n}$
(C) $\eta_{c}<\eta_{t}<\eta_{i}<\eta_{n}$
(D) $\eta_{c}<\eta_{i}<\eta_{t}<\eta_{n}$

View Topper Answer

We hope we have given the updated helpful answer / content for your query in an easily accessible format to help you in preparing adequately. We do offer free support materials, 11th maths guide 11th maths guide 12th maths guide 10th maths guide, also for all the classes books and guide to all the students who sign up for SaraNextGen. Apart from traditional textbook queries, we've got conjointly provided further high order level thinking issues, that are seemingly to be expected in boards and competitive exams. It includes conceptual queries, MCQs, Long and short answer type queries, etc. These Questions are designed to learn each student and academics by providing chapter-wise further issues focusing totally on testing conceptual information with applications. Here, we've got provided a number of the necessary ways in which within which the solutions of all the Questions will profit students of class 1 to 12. If you have any queries, drop a message to us and we will get back to you at the earliest.