Thermal analysis on the letter mark spot of the corvette Cheonan-hit torpedo

Dispute is going on over the letter mark on the torpedo that is believed to have sunk the Korean corvette Cheonan in March, 2010. This research is made to investigate if the spot has experienced temperature high enough to burn, which can be proof of later fabrication. Conditions to maximize the heating are introduced and the temperature is calculated numerically as the explosion 'bubble' expands underwater, the gas stream heats the disk front surface and heat is conducted to the letter-written rear surface. Results show less than 20 degrees C rise everywhere in the torpedo propulsion part and essentially no temperature rise on the letter mark over extensive tests. Therefore, the assertion that the letter mark should have been burnt turns out to be fallacious.