Cp is increasing with increase in TSR and never decrease in 2D Unsteady analysis

HUSSAIN MAZARBHUIYA · October 12, 2017, 02:27

Dear friends,
I am trying to simulate 3 bladed H-Darrieus VAWT rotor considering 2D unsteady analysis using fluent. Rotor details are in below:
airfoil chord length=5 cm
rotor diameter=50cm
rotor height=50 cm
wind speed=6.0 m/s
when i was calculating Cp from Cm values for each angular velocity, i found that Cp was increasing with increase in TSR and never decrease after the pick value of Cp. which was not the actual trend of Cp vs TSR graph for VAWT rotor. Can anyone detect where i am doing wrong. Please give necessary information and help me to solve the issue.

Thanks.

leee · January 17, 2018, 01:58

Hi.... I am getting the same problem.. In my case i am using a 3D unsteady using CFX. My Cp value is increasing with respect to TSR but never gets down even till 4TSR.

yanyan067 · January 24, 2018, 13:47

Hello,
Did you solve the problem?

leee · February 12, 2018, 11:31

When I tried upto 5 TSR . The Cp started decreasing . But in my case it needs to get down before 3 TSR

October 12, 2017, 02:27	Cp is increasing with increase in TSR and never decrease in 2D Unsteady analysis	#1
HUSSAIN MAZARBHUIYA New Member Join Date: Oct 2017 Posts: 2 Rep Power: 0	Dear friends, I am trying to simulate 3 bladed H-Darrieus VAWT rotor considering 2D unsteady analysis using fluent. Rotor details are in below: airfoil chord length=5 cm rotor diameter=50cm rotor height=50 cm wind speed=6.0 m/s when i was calculating Cp from Cm values for each angular velocity, i found that Cp was increasing with increase in TSR and never decrease after the pick value of Cp. which was not the actual trend of Cp vs TSR graph for VAWT rotor. Can anyone detect where i am doing wrong. Please give necessary information and help me to solve the issue. Thanks.

January 17, 2018, 01:58	Same Problem	#2
leee New Member Leelakrishnan Join Date: Jan 2018 Location: Chennai, India Posts: 4 Rep Power: 8	Hi.... I am getting the same problem.. In my case i am using a 3D unsteady using CFX. My Cp value is increasing with respect to TSR but never gets down even till 4TSR.

January 24, 2018, 13:47	Same question	#3
yanyan067 New Member Cambridgeshire Join Date: Sep 2016 Posts: 1 Rep Power: 0	Hello, Did you solve the problem?

February 12, 2018, 11:31		#4
leee New Member Leelakrishnan Join Date: Jan 2018 Location: Chennai, India Posts: 4 Rep Power: 8	When I tried upto 5 TSR . The Cp started decreasing . But in my case it needs to get down before 3 TSR