https://forums.autodesk.com/t5/cfd-forum/how-to-calculate-drag-coefficient-of-the-model/m-p/13822241#M27014 <P>Hello,<BR />I am currently calculating the drag coefficient of a rectangular prism model placed in a uniform flow. However, the result I obtained is <STRONG>1.3</STRONG>, which is smaller than the value reported in previous studies (approximately <STRONG>2.0</STRONG>).</P><P>The parameters I used for the calculation are as follows:</P><UL><LI><P>Wind velocity: 32 m/s (assumed constant with height)</P></LI><LI><P>Model dimensions: width × depth × height = 10.24 m × 10.24 m × 37.42 m</P></LI><LI><P>Air density: 1.22 kg/m³</P></LI></UL><P>I have uploaded my model data at the link below. I would greatly appreciate it if you could kindly review it and let me know where I might be making a mistake.<BR /><BR /><A href="https://drive.google.com/drive/folders/1tYOPzNB17_d6Wdnz1oEJzdrUBdXFSBN_?usp=drive_link" target="_blank" rel="noopener">https://drive.google.com/drive/folders/1tYOPzNB17_d6Wdnz1oEJzdrUBdXFSBN_?usp=drive_link</A></P> Tue, 23 Sep 2025 15:15:13 GMT 20415044mm 2025-09-23T15:15:13Z https://forums.autodesk.com/t5/cfd-forum/how-to-calculate-drag-coefficient-of-the-model/m-p/13822241#M27014 <P>Hello,<BR />I am currently calculating the drag coefficient of a rectangular prism model placed in a uniform flow. However, the result I obtained is <STRONG>1.3</STRONG>, which is smaller than the value reported in previous studies (approximately <STRONG>2.0</STRONG>).</P><P>The parameters I used for the calculation are as follows:</P><UL><LI><P>Wind velocity: 32 m/s (assumed constant with height)</P></LI><LI><P>Model dimensions: width × depth × height = 10.24 m × 10.24 m × 37.42 m</P></LI><LI><P>Air density: 1.22 kg/m³</P></LI></UL><P>I have uploaded my model data at the link below. I would greatly appreciate it if you could kindly review it and let me know where I might be making a mistake.<BR /><BR /><A href="https://drive.google.com/drive/folders/1tYOPzNB17_d6Wdnz1oEJzdrUBdXFSBN_?usp=drive_link" target="_blank" rel="noopener">https://drive.google.com/drive/folders/1tYOPzNB17_d6Wdnz1oEJzdrUBdXFSBN_?usp=drive_link</A></P> Tue, 23 Sep 2025 15:15:13 GMT https://forums.autodesk.com/t5/cfd-forum/how-to-calculate-drag-coefficient-of-the-model/m-p/13822241#M27014 20415044mm 2025-09-23T15:15:13Z https://forums.autodesk.com/t5/cfd-forum/how-to-calculate-drag-coefficient-of-the-model/m-p/13850244#M27076 <P>It's always fun to use this to calculate terminal velocity. You can get pretty accurate with just order-of-magnitude numbers. Say you have a skydiver who weights 75 kg, and the gravity force on him is 750 N. Assume the drag coefficient is 1/2, his frontal area (falling flat) is 1 m2, and the density of air is 1 Kg/m3. At terminal velocity, drag force = gravity force, so u2 = 2Fd/ρCdA = 2 * 2 * 750 = 3000 m2/s2 so u = 55 m/s which is surprisingly close to what wikipedia says.&nbsp;<SPAN><A href="https://9apps.ooo/" target="_blank" rel="noopener">https://9apps.ooo/</A></SPAN></P> Wed, 29 Oct 2025 04:11:08 GMT https://forums.autodesk.com/t5/cfd-forum/how-to-calculate-drag-coefficient-of-the-model/m-p/13850244#M27076 wukanrukal 2025-10-29T04:11:08Z