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About CFD Online

CFD Online is an online center for Computational Fluid Dynamics. Services include several discussion forums, a jobs database, a free CFD reference in the form of a CFD-Wiki, a news and announcement forum, a books guide, an events calendar, and a comprehensive annotated link section with pointers to CFD resources around the world. CFD Online's goal is to offer high-quality web services to the CFD community. The site is independent and it is financed mainly by banner-ads.

Today CFD Online is the largest and most popular CFD site on the Internet. During a typical week the web site is visited by more than 68,000 people (unique IP addresses), downloading 480,000 web pages per week. In total there are more than 8,000 web sites around the world with links to CFD Online. In 2014 CFD Online celebrated 20 years of uninterrupted service to the CFD community! CFD Online continues to grow and strengthen its position as the world's leading CFD portal. CFD Online is top-listed by all major search engines and has received many awards over the years.


2014 was a very successful year for CFD Online. For the first year ever CFD Online on average delivered more than 2 million web-pages per month to visitors! Both the number of read web pages and the number of unique visitors (IP addresses) reached new record levels. The number of read web-pages increased by 7% and the number of unique visitors increased by 11% compared to the previous year. The new forum section, launched in March 2009, has continued to develop very well and has helped to increase the traffic in 2014. The bar chart above shows the 12-month trailing average of the number of web pages delivered from CFD Online per month over the previous 16 years. As can be seen, web-site traffic to CFD Online continues to grow steadily year after year.

Note that these statistics exclude access from robots and common search engines like Google and Yahoo. This is necessary in order to give a true representation of the traffic from real humans. Otherwise the quickly growing traffic from Google and other search engines robots would completely overshadow human visitors.

Visitor Demographics

Visitors to CFD Online come from typical CFD sites from all over the world. The pie chart below shows the traffic distribution across different top-level domains. Further details about where traffic is coming from can be found in the web server statistics report at or in the most recent web-server statistics.

Visitor demographics are similar to last year. The trend with a decreasing traffic from India has continued and India now only accounts for 2% of all traffic. Another interesting observation is that China for the first year is in the top-10 list, the reason for this is probably that some of the traffic from China is no longer hidden behind an anonymous IP address. Traffic from Germany remains very strong and is now more than twice as big as the second European country, United Kingdom. The reason is the growth of the German economy combined with the strong usage of OpenFOAM in Germany. More and more companies are now hiding behind anonymous numerical or network addresses and this makes it increasingly difficult to locate where traffic is coming from. On the browser side Chrome (38%) continues to grow quickly and will soon have passed Firefox (38%) as the most popular browser. Usage of Internet Explorer continues to fall (15%).


The pie chart below shows the relative number of page-downloads for the different services at CFD Online. In total, the discussion forums are still the most popular section, with 54% of all the page-views. The CFD-Wiki has 14%, the Events calendar 12%, the CFD Jobs Database 9%, and the Links section 2% of all page-views.

The strong growth in traffic to the discussion forums seen in previous years has continued also in 2014. CFD Online remains the most popular meeting place on the net for free and independent discussions about CFD. Users seem to prefer the open forums at CFD Online over closed forums run by code vendors. The following services are currently available at CFD Online:

News and Announcement Service

The largest free online CFD news service. The news section has 4,200 unique visitors every month and more than 4,400 people are subscribed to the weekly email news-digest.

Discussion Forums

The most popular meeting place on the net for people interested in CFD. The forums have more than 510,000 archived messages in 130,000 threads from the previous 17 years. In 2014 forum traffic continued to grow quickly.


CFD-Wiki is intended to eventually become the ultimate free CFD reference and text-book. The content is written collaboratively by thousands of users. CFD-Wiki contains more than 550 articles on various CFD related subjects. Many engineers and students use it as a valuable reference.

Links Section

The links section is very well known in the CFD world and continues to attract many return visitors year after year. It has been the largest collection of CFD links available on the net since it was introduced in 1994. In 2012 a major overhaul of the whole links section was done.

CFD Jobs Database

The CFD Jobs Database is the section that attracts most people. The CFD Jobs Database is visited by more than 1,400 job-seekers every day! It is a very good way to recruit CFD experts. The CFD Jobs Database has had more than 200 open positions advertised throughout 2014.

CFD Books Guide

The Books Guide is intended to assist students and professionals in finding good CFD books. The guide includes more than 200 books. A book-rating system allows readers to review books.

Events Calendar

This service is intended to help students and professionals to find CFD related conferences, courses and workshops. The calendar currently includes 45 upcoming CFD events and since the service was opened in 2002 more than 2,200 events have been advertised in it.

Tools Section

The tools section contains online tools useful for CFD engineers and students: Two calculators, a unit converter, a Y+ estimation tool and a tool to convert and estimate turbulent properties.

Feeds Section

The feeds section was launched in 2012; it contains aggregated feeds of CFD news-sources, blogs, vendors, jobs and journals. This service has become an important tool to help people stay up to date.


CFD Online is only responsible for the documents on this server, not for any of the external references. All opinions expressed are personal opinions.

Software and Hardware

CFD Online is hosted on a Centos KVM based virtual server. The virtual server is running on a dedicated production server with a failover backup server standing online to take over in case of hardware problems on the main production node. Our servers are located in Germany. We moved to Germany in June 2015. Before that CFD Online was hosted in the US.

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Our latest production server was bought in May 2015. It has a Xeon E3-1270v3 CPU, 32GB ECC RAM, and two mirrored RAID1 enterprice SSD disks to ensure a quick and reliable delivery of pages.


Please tell us what you think about this site. Contact information can be found on the contacts page. We appreciate any comments or suggestions. It is always nice to get some feedback and not only strange connections from someone.far.away.sirius_b
"I consider it the obligation of scientists and intellectuals to ensure that their ideas are made accessible and thus useful to society instead of being mere playthings for specialists."

- Bjarne Stroustrup, from "Design and Evolution of C++"