List of top Naval Architecture and Ocean Engineering Questions

Which one of the following psychrometric processes is represented by the line 1-2 in the figure? 

A uniform flow, a point source of strength \( +\sigma \) at \( (a, 0) \) and a point sink of strength \( -\sigma \) at \( (-a, 0) \) are shown in the figure. The velocity potential \( \phi \) resulting from the superposition of these flow fields is given by 


 

Consider the \( 2\pi \)-periodic function defined by \( f(x) = \begin{cases} -1, & \text{if } -\pi < x \leq 0, \\ 1, & \text{if } 0 < x \leq \pi. \end{cases} \) 
Which of the following is/are correct about its Fourier series expansion, \( \frac{a_0}{2} + \sum_{n=1}^\infty a_n \cos nx + b_n \sin nx \)?

Consider the flow past a curved wall as shown in the figure. Which of the following statement(s) is/are correct? 

If \( X \) is a Poisson random variable with mean \( \mu = 1 \), then the conditional probability of the event \( \{ X \geq 2 \} \) given that the event \( \{ X \geq 4 \} \) has occurred, is ……… (rounded off to two decimal places).
 

The value of the triple integral \(\iiint (xy^2 + yz^3) \, dx \, dy \, dz\) over the region given by \(-1 \leq x \leq 1\), \(3 \leq y \leq 4\), \(0 \leq z \leq 2\), is .

A 4-cylinder, 4-stroke diesel engine operating at 3000 rpm has a compression ratio \(r\) of 12 and cut-off ratio \(r_c\) of 2.5. The temperature rise during the heat addition process is 2400 K. The efficiency of an air-standard diesel cycle is given by: \[ \eta = 1 - \frac{1}{r^{\gamma-1}} \left( \frac{r_c^\gamma - 1}{\gamma (r_c - 1)} \right). \] Assume the working fluid as air with a mass flow rate of 0.05 kg/s, \(\gamma = 1.4\), and \(C_p = 1.004 \, \text{kJ/kg-K}\). The power output of the engine is …… kW (rounded off to the nearest integer).
 

A single degree of freedom system has a mass, stiffness, and damping of 200 kg, 20 N/m, and 62 N-s/m respectively. For a forced oscillation system, if the excitation frequency is equal to the undamped natural frequency, then the dynamic magnification factor is  ………….(rounded off to three decimal places).
 

The wave spectrum and the ship heave Response Amplitude Operator (RAO) are shown in the figure. The variance of the heave motion is …… m\(^2\) (rounded off to three decimal places). 

Consider a thin-walled closed cylindrical steel vessel with an internal pressure of \(2 \, \text{N/mm}^2\). The inner diameter is \(1 \, \text{m}\), and the thickness of the wall is \(10 \, \text{mm}\). The hoop stress is ……….. \(\text{N/mm}^2\) (rounded off to one decimal place).

A propeller disc of diameter \(2 \, \text{m}\) produces a thrust of \(88 \, \text{kN}\) while advancing at a speed of \(5 \, \text{m/s}\) in fresh water of density \(1000 \, \text{kg/m}^3\). Based on the axial momentum theory, the propeller efficiency is ………….. % (rounded off to one decimal place).
 

Consider a rectangular plate with in-plane loads. The stress at an arbitrary angle \( \theta \) is given by \( \sigma_x \), \( \sigma_y \), and \( \tau_{xy} \) as shown in the figure. If the principal plane is at \( \theta = 45^\circ \), and the principal stresses are \( \sigma_x = 8 \, \text{N/mm}^2 \) and \( \sigma_y = 3 \, \text{N/mm}^2 \), then the corresponding \( \tau_{xy} \) is …………… \( \text{N/mm}^2. \) 

A ship of 5000 tonnes displacement has a rectangular tank 6 m long and 10 m wide, half-filled with oil of relative density 0.8. The virtual reduction in the transverse metacentric height of the ship due to the free surface effect of the oil in the tank is ……….. cm.
 

An ocean wave of period 8 s and height 2 m is propagating in the Indian Ocean from south to north. According to linear wave theory, for the wave to be considered as a deep-water wave, the minimum water depth should be …………. (rounded off to the nearest integer). 
 

Consider a gas turbine combustor with air as the working fluid. The flow enters the device at 500 K and leaves at 1400 K with a mass flow rate of 0.1 kg/s. The changes in kinetic energy and potential energy of the flow are neglected. Assuming \( C_p = 0.717 \, \text{kJ/kg-K} \) and \( R = 0.287 \, \text{kJ/kg-K} \), the rate of heat addition is  kW (rounded off to the nearest integer). 
 

Consider a circular cylinder of diameter 0.5 m and length 2 m, rotating in clockwise direction at a speed of 100 rpm in a flow of velocity 2 m/s. Assume the density of the fluid as 1.225 kg/m\(^3\) and \( \pi = 3.14 \). By Kutta-Joukowski theorem, the lift force on the cylinder is \(\_\_\_\_\_\) N (rounded off to the nearest integer).