A lot of properties were studied by different scientists ofwhich the SAND GRAIN ROUGHNESS HEIGHT and the size of SAND GRAIN were definedby Schlichting and Nikraudse respectively. Depending upon the ks+ value thereare 3 ranges that came to exsistence  ks< 4 hydraulically smooth regime 470 fully rough regime It was nonted that all the rougnessfunction collapsed in only one regime that is FULLY ROUGH REGIME Fundamentally there aer various wasystoachieve a desirsed value of K+ by changing k/ ?And Re? IT has benn verified that differentflows having the same K+ should produce the same U+ .The deviatuijns were found only inone case for Re?= 120 . Hence Re? =180 was chosen as Reynolds numbers for DIRECT NUMERICALSIMULATION for sinusoidal pipe roughness.

The difference between MEANCENTERLINE VELOCITIES Vc/U ?For rough and smooth wall cases and for  constant Re ? are used for the computation ofvalues for  U+ .Roughness and flow are relates insuch a way thtat when flow approaches hydrodynamically smooth conditios androughness decreasas the statics more ssenstive to domain size.Plotting thegraph of MEAN VELOCITY STATICS provides the differences in immediate viscinityof rough wall.  5. Summary and concluding remarks A thourough study of TRI in a radiativeturbulent channelflow has been performed. Themodification of the temperature field upon varying theoptical thickness has been extensivelyinvestigated with the aid of temperature variancebudgets and turbulent temperaturespectra.We see that there are different magnitudes and qualitative behavioursof TRI when different optical depths are put to test, andhighlight specifically the contrastingeffects of radiative absorption and emission onTRI.For a low optical thickness (?        ) the role of absorption is limited tothemodification of mean profiles since  there is no change in localthermal fluctuations  due to incident radiation (G) .

On the otherhand the whole temperature spectrum can be disrupted by emission,stabilizingtemperature and reducing thermal fluctuations mainly in thechannel core. Thedirect effect of radiation on temperature variation is thus dependent  only on emission, and has a relatively smallimpact due to the low absorption coefficient