0 . 0 1 ▁N / m 2 . ▁ ▁Reyn olds ▁number ▁of ▁the ▁flow ▁is ▁defined ▁as ▁the ▁ratio ▁of ▁in ert ia ▁forces ▁to ▁vis c ous ▁forces . ▁Mathemat ically ▁it ▁is ▁written ▁as ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▁Where ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▁= ▁density ▁of ▁fluid ▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▁v ▁= ▁velocity ▁of ▁fluid ▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▁d ▁= ▁characteristic ▁length ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▁= ▁dynamic ▁vis cos ity ▁of ▁fluid ▁ ▁The ▁Reyn olds ▁number ▁helps ▁us ▁to ▁predict ▁the ▁transition ▁between ▁l amin ar ▁and ▁tur bul ent ▁flows . ▁L amin ar ▁flow ▁is ▁highly ▁organized ▁flow ▁along ▁stream lines . ▁As ▁velocity ▁increases , ▁flow ▁can ▁become ▁dis organ ized ▁and ▁cha otic . ▁This ▁is ▁known ▁as ▁tur bul ent ▁flow . ▁L amin ar ▁flow ▁occurs ▁in ▁flow ▁environments ▁where ▁Re ▁< ▁ 2 0 0 0 . ▁Tur bul ent ▁flow ▁is ▁present ▁in ▁circumstances ▁under ▁which ▁Re ▁> ▁ 4 0 0 0 . ▁The ▁range ▁of ▁ 2 0 0 0 ▁< ▁Re ▁< ▁ 4 0 0 0 ▁is ▁known ▁as ▁the ▁transition ▁range . ▁Most ▁blood ▁flow ▁in ▁humans ▁is ▁l amin ar , ▁having ▁a ▁Re ▁of ▁ 3 0 0 ▁or ▁less , ▁it ▁is ▁possible ▁for ▁tur bul ence ▁to ▁occur ▁at ▁very ▁high ▁flow ▁rates ▁in ▁the ▁desc ending ▁a ort a , ▁for ▁example , ▁in ▁highly ▁condition ed ▁athlet es . ▁Tur bul ence ▁is ▁also ▁common ▁in ▁path ological ▁conditions ▁such ▁as ▁heart ▁murm urs ▁and ▁st en otic