Project Overview

NLAW Flight Path Analysis via Parametric CFD Simulation in ANSYS Discovery, This project predicts NLAW missile trajectory by varying fin angles (1°-25°) with the speed of 100 m/s, analyzing aerodynamic forces and 2-second Flight Path Deviation through steady-state CFD simulations and numerical trajectory integration.

This analysis measures yaw deviation (θy) in the XY plane and pitch deviation (θz) in the XZ plane relative to the missile's longitudinal axis (X-axis). The total deviation angle (θtotal) , providing the 3D flight path deviation from the straight-line trajectory for each fin incidence angle.

Objectives

After the CFD force analysis described above, this project calculates accelerations For NLAW using Newton's second law (a = F/m) from aerodynamic forces obtained at each fin angle. Using 15° incidence as a representative example, velocities are iteratively computed for various time steps (dt = 0.1s) via Euler integration: V_new = V_old + a × dt. Positions are then determined using X_new = X_old + V_old × dt, Y_new = Y_old + V_y_old × dt, and Z_new = Z_old + V_z_old × dt, providing precise trajectory prediction and lateral deviation quantification throughout the 2-second simulation period.

Results and Discussion

The CFD simulations demonstrate a clear trend: drag force steadily increases from 22.5N at 1° to 104N at 25° fin incidence. Lateral forces (Fy, Fz) are highest at low angles, causing maximum trajectory deviation of 6.93m at 3°, but progressively cancel out toward higher angles.

15° case study (t=2s) shows controlled deceleration with minimal drift (Y=-4.32m, Z=+1.04m), confirming the 11°-23° operating window balances roll stability and trajectory accuracy for effective Predicted Line of Sight guidance.