Clyde's, the Georgetown restaurant that for 15 years has been a watering hole for young professionals and for people who want to look at young professionals, is expanding to Tysons Corner in Fairfax County.

The new restaurant, which will be located in a $3.6 million building to be completed in the fall of 1979, will be called Clyde's of Tysons Corner.

According to co-owner Stuart C. Davidson, the planned restaurant, which will be about twice as big as Clyde's of Georgetown, "will have so much charm it will drag you out of your condominium at night."

Clyde, Inc., which includes a second suburban Clyde's in Columbia, Md., takes in about $6 million a year in operating revenue in the Washington area, according to Davidson. He said the planned restaurant on Leesburg Pike in Vienna is projected to take in $5 or $6 million a year, making it one of the largest restaurants in suburban Washington.

The decision to build the restaurant at Tysons Corner, Davidson said, came after studying the area for more than a year and reviewing the results of survey by Real Estate Research Corporation of America, which told the restaurant company that 13,000 Department of Assessments and Taxa-people work in the Tysons Corner area.

"We have a lot of business from the suburbs," Davidson said, referring to his Georgetown restaurant. "But our typical customer doesn't have any place out there (in Fairfax County) that he likes. With the parking problems, he sure isn't going to come into Georgetown every night."

The restaurant will have room for 450 people, dining and drinking in the four dining rooms and two bars, according to building plans. Dining rooms on the first floor will have glass skylights. Robin Hill, an Australian-born painter, has been commissioned to paint a series of paintings for the restaurant.